In this review, we will take a detailed look at the best radar detectors under $100 available on Amazon. It is our intention to provide you with the information that you need to purchase the right radar detector that meets your requirements.
You will only find radar detectors under $100 in this review. There are a lot of radar detectors available for this price so we had to look at many of them to choose the best 10 for you to consider buying.
You will see an individual review for every radar detector that made our list. We will tell you what we thought about each device, its features and benefits, the pros and cons of each model, and also what the customers thought about every radar detector. Below is an overview of the best radar detectors under $100 in our final list:
| Ranking | Product | Features | Our Rating | Check Price |
|---|---|---|---|---|
#1. | Uniden DFR3 Long Range Laser/Radar Detector |  (4.7 / 5) |  (4.6 / 5) | CHECK PRICE ON AMAZON |
#2. | Cobra RAD 350 Laser Radar Detector | (4.7 / 5) |  (4.4 / 5) | CHECK PRICE ON AMAZON |
#3. | Cobra ESD7570 Radar Laser Detector | (4.7 / 5) |  (4.2 / 5) | CHECK PRICE ON AMAZON |
#4. | Whistler XTR-450 Cordless Radar Detector | (4.7 / 5) |  (3.8 / 5) | CHECK PRICE ON AMAZON |
#5. | Cobra XRS9370 High Performance Radar Laser Detector | (4.6 / 5) |  (3.6 / 5) | CHECK PRICE ON AMAZON |
#6. | Whistler XTR-145 Laser Radar Detector | (4.6 / 5) |  (3.5 / 5) | CHECK PRICE ON AMAZON |
#7. | Cobra SPX 900 14 Band High Performance Radar Laser Detector | (4.6 / 5) | (3.5 / 5) | CHECK PRICE ON AMAZON |
#8. | Cobra ESR800 12 Band Radar Detector | (4.6 / 5) | (3.5 / 5) | CHECK PRICE ON AMAZON |
#9. | Rocky Mountain RMR-D540 Radar Detector | (4.7 / 5) |  (3.3 / 5) | CHECK PRICE ON AMAZON |
#10. | Whistler CR75 Laser Radar Detector | (4.6 / 5) | (3.3 / 5) | CHECK PRICE ON AMAZON |
Table of Contents
What are the Radar Detectors?
If you are a driver then you are probably always concerned about getting a speeding ticket. You just never know when a police radar will catch you traveling at a higher speed than you should be. This is where a radar detector comes in. It will enable you to relax and enjoy your driving more and make you aware of any police radar on the horizon.
Radar waves are not visible to the human eye and a good radar detector can detect the radar waves used by authorities to measure how fast you are traveling in your vehicle. When the device detects these invisible speed radar waves it will produce an alarm to warn you about them. This is usually an audible alert.
On hearing this alarm it is then up to you what you do. The sensible thing would be to reduce your speed so that you can avoid receiving a speeding ticket. An invisible radar wave could also indicate a road hazard such as construction work. Whatever the purpose of the radar waves your radar detector will let you know that they are there.
Some radar detectors are able to identify the use of laser speed guns which work in a different way to conventional radar for measuring vehicle speed. The authorities have been using radar to check vehicle speeds for many years. A radar transmitter and receiver can identify speed and distance and can tell how far away a car is and how fast it is traveling.
How do Radar Detectors work?
A radar device such as a speed gun uses a radio transmitter that oscillates electric current so that the voltage changes at a specific frequency. This will generate electromagnetic energy and this can travel through the air in the form of an electromagnetic wave.
The radar transmitting device will also include an amplifier that increases the strength of the electromagnetic wave and an antenna used to broadcast this wave into the air. The radar device will also have a radar receiver component.
The receiver element of the radar device detects electromagnetic waves via an antenna and will then convert them to electrical current for measurement of speed and distances. If something gets in the way of a transmitted electromagnetic wave then it reflects part of the energy of that wave.
This causes the wave to bounce back to the device that transmitted it at the speed of light. The amount of time it takes a radar wave to return determines how far away a particular object is.
So how does a radar device measure the speed that a vehicle is traveling? It uses something called a “Doppler shift” to achieve this. All radar waves operate at a specific frequency which is essentially the number of oscillations per second. If a radar wave bounces off of a still object then the return signal or “echo” has the same frequency.
But if an object, such as a car, is in movement then each part of the radar wave reflects at a different point and changes the overall pattern of the wave. If a vehicle is moving away from the radar wave then the second occurrence of the wave has to travel further to reach the vehicle and this will cause the frequency to reduce.
In a situation where a vehicle is moving towards the radar signal, the second wave segment travels a shorter length which results in the peaks and troughs of the wave squeezing together. This will increase the frequency of the wave.
The radar device can calculate how fast a vehicle is moving away from the radar wave or towards it. Sometimes the police use radar guns in police cars that are moving as well, so the speed of the police vehicle needs to be accounted for.
If the police vehicle is traveling at 40 miles per hour and the radar device detects that another car is moving away from it at 20 miles per hour then that car will be traveling at 60 miles per hour. When the radar device detects that the target car isn’t moving away or toward the radar wave then it must be traveling at the same speed of 40 miles per hour.
These days police departments are using more sophisticated technology to track the speed of vehicles on the road. A lot of authorities now use laser-speed guns that use concentrated light instead of traditional electromagnetic waves. These are lidar (light detection and ranging) radar devices.
A lidar gun does not measure frequency changes but emits many bursts of infrared lasers very quickly for a number of distances. The device compares these distance samples to calculate the speed of the vehicle. Lidar guns emit several hundred laser samples in less than 500 milliseconds which makes them very accurate.
Speed cameras now use lidar devices as well. The devices will shine a laser beam across the width of the road and detect the speed of any vehicle that passes through the beam. The device makes adjustments for the different angles of view to accurately calculate the speed.
It is really easy for a radar detector to detect conventional electromagnetic radar waves. A simple radar detector is really a radio receiver similar to the one that you might use to tune in to your favorite radio station.
With a basic radar detector, you will not have much protection. If the police decide that you are a target then they can be onto you in a flash and although the radar detector detects the signal it is already too late.
What a radar detector does is scan a specific area for specific signals, in particular, those used for speed detection by the authorities. If a police officer is in the distance with a radar gun turned on then a radar detector will pick this up and warn you in good time to slow down. More advanced radar detectors have the technology to pick up laser beams from lidar devices.
Some radar detectors have a laser jamming feature. Here a number of LEDs emit a light beam that makes it harder for a lidar speed device to accurately measure the speed of your vehicle. These do not work 100% of the time but can certainly provide a level of protection against speeding tickets.
You need to be aware that there are different types of radar systems. X-band radar uses low-frequency signals that have a high output and a good radar detector can pick these signals up 2 to 4 miles away.
A lot of police departments now use K band radar which uses a shorter wavelength than X band and this can be tricky to detect in time. A radar detector that has a K band detection feature will normally provide an alert anywhere between half a mile and two miles in the distance.
Who needs a Radar Detector?
If you live in a state where the use of radar detectors is legal then you need one. No matter how careful a driver you are there are going to be times when you break a speed limit – often without even realizing it.
It doesn’t matter that you didn’t break the law intentionally. If the authorities catch you speeding with a radar device then you are highly likely to get a speeding ticket. There are a number of scenarios where you may fall foul of a radar gun and a speeding ticket.
Some roads have varying speed limits and you may be moving from one section of the road to another not reducing your speed to stay within the law. Traveling down a hill often catches people out as by the time they reach the bottom they have broken the speed limit.
At the end of the day, people are in a hurry these days. A lot of people will drive too fast and run the risk of getting a speeding ticket each time they use the road. A radar detector offers a degree of protection against this so it is a wise investment.
Best Radar Detectors Under $100 Dollars Amazon: Updated 2024
We spent a lot of time looking at a lot of radar detectors under $100 to determine which of these would make our top ten list. We looked at several factors such as the features of the radar detector, the ease of use, and of course the price.
You will find a detailed review of all ten of these best radar detectors under $100 below. We will tell you about the features of each device and its pros and cons. From this, you can decide which radar detector is right for you.
1. Uniden DFR3 Long Range Laser/Radar Detector Review
This radar/laser detector offers plenty of features for the money. When installed this detector provides protection all around your car (360°) and it has 3 modes that you can use which are “Highway”, “City” and “City1”.
There is an audible alarm with the Uniden DFR3 Long Range Laser/Radar Detector and at the front of the device is a display that will show an icon to represent the type of radar or laser signal detected. It also displays the signal strength from 1 to 5. We found that the display was clear and easy to read at a glance while driving.
This detector is able to pick up on the most commonly used radar bands X, K, and Ka and will detect the use of lidar lasers too. If the device detects a laser it will display an “L” icon. In our tests, this radar/laser detector performed really well and alerted us immediately to both radar and laser signals. It can also detect POP radar.
The Uniden DFR3 Long Range Laser/Radar Detector is a small device measuring just 7.8 inches by 5.6 inches by 2 inches. You can easily conceal it in your car. It weighs under 11 ounces too.
This detector does come with a windshield mount but we recommend that you use the mounting bracket supplied instead to mount the device low. You will also receive a wiring harness when you purchase this device.
- Detects radar and laser.
- Accurate performance.
- Comes with everything you need.
- Usually available for just under $100.
2. Cobra RAD 350 Laser Radar Detector Review
This radar laser detector has some good features and has a very useful “instant on” feature which is able to detect any new signal threats for increased protection. It can detect laser and radar signals from the front and back of your vehicle and will pick up on X, K, and Ka radar and display the signal strength and laser signals too.
The Cobra RAD 350 Laser Radar Detector performed very well when it came to minimizing false alerts. It uses a patented technology called the IVT Filter System and this was effective at reducing false alerts from things like collision avoidance systems. You only get alerts about signals that matter.
There are different audible tones for band identification and signal strength. These alerts could have been a little louder as they were hard to hear in noisy traffic conditions. The device also has a 7 segment display in color to show you band icons and the strength of signals.
In our tests we found this laser radar detector to be reliable and accurate. The device is really easy to use and it is simple to install in your car. We really liked the “instant-on” feature which we found could detect new signals immediately. This is another lightweight device weighing just over 11 ounces and measuring 4.1 inches by 2.6 inches by 1.4 inches.
- Detects all radar bands and laser.
- Minimizes false alerts.
- Immediate detection of new threats.
- Audio alerts are not loud enough.
3. Cobra ESD7570 Radar Laser Detector Review
This is another radar laser detector that has some good features. It has both a city and highway mode for different types of driving which you can switch between using a single button. The device also offers 360° protection against laser signals.
We were pretty impressed with the range of detection with the Cobra ESD7570 Radar Laser Detector. We found that in city mode it would detect signals up to 4-5 blocks away and in highway mode, it was good at detecting signals up to half a mile away. This means that you should have adequate time to slow down.
The display on this radar laser detector is really bright and clear. There is a button to control the brightness if you need it. All alerts are audible and you can mute an alert if it is continually sounding.
We liked the audible alarms as they are clear and loud. The display was impressive too and when the device detects a signal it displays a graph showing signal strength to help you assess how far away the threat is.
These days some law enforcement agencies are using VG-2 technology to try and detect who is using a radar laser detector. The Cobra ESD7570 Radar Laser Detector can detect this kind of surveillance and will alert you to this. The device is very lightweight at less than 5 ounces and measures just 2.7 inches by 1.3 inches by 4.1 inches.
- The good range gives plenty of warning.
- Alerts and displays are very clear.
- VG-2 alert feature.
- Other devices can detect more bandwidths.
4. Whistler XTR-450 Cordless Radar Detector Review
Although this is a radar detector it will detect lidar laser signals as well. The most unique thing about this device is that it is cordless. It uses three AA Ni-MH batteries which you can recharge. You can recharge the batteries by plugging the device into the cigarette lighter. When fully charged the batteries will last around 12 hours.
The Whistler XTR-450 Cordless Radar Detector has clear audio alerts and a bright blue colored LCD display. You will see the type of signal detected as well as the signal strength. There are 3 city modes and highway modes. There is also a stay alert feature which helps the driver with their level of alertness.
Some people don’t like the idea of a cordless device as they worry about the batteries discharging and the device being inoperable. This detector has an automatic shut-off feature if you forget to turn it off when you leave your vehicle. You can configure the amount of time to shut off.
This low-cost radar detector has some good features such as a VG-2 detector to warn about surveillance and POP mode detection. A lot of police forces are using the new radar pop-gun which is difficult to detect. This model has patented POP protection which is effective.
The Whistler XTR-450 Cordless Radar Detector performed pretty well in our tests. It has a reasonably good range but we did encounter a lot of false alerts. This device is lightweight at 9 ounces and it is compact measuring 4.9 inches by 3.1 inches by 1.4 inches.
- Cordless with auto shut off.
- POP technology and VG-2 Detection.
- The price is reasonable.
- The display screen could be better.
5. Cobra XRS9370 High-Performance Radar Laser Detector Review
This is another reasonably priced radar laser detector from Cobra which is a leading company in the field. You will have protection from 14 radar and laser bands with this device and it also has a POP mode and can detect VG-2 surveillance.
The Cobra XRS9370 High-Performance Radar Laser Detector has a super “fast sweep” technology that extends the range of detection. There are highway and city modes and this detector will pick up KU band signals which are in Europe now and on their way to the United States.
You get all-around protection for your car with this device. There are audible alarms for the different types of signals and a bright display that will show you the type of signal detected and the signal strength. We did experience a number of false alarms though.
In our tests, this radar laser detector performed well. The range was good but not as impressive as Cobra’s claims. Other devices had a better range. It is really lightweight at less than 5 ounces and it is small measuring 2.8 inches by 1.3 inches by 4.2 inches.
- Rapid detection technology.
- POP and VG-2 protection.
- Clear display and alerts.
- The range is not as good as claimed.
6. Whistler XTR-145 Laser Radar Detector Review
This is radar and laser protection at a very good price. It will detect all laser signals and the most commonly used radar bands X, K, and KA. It also has VG-2 detection to warn you about radar detector surveillance. You get 360° protection with this device from all threats.
The Whistler XTR-145 Laser Radar Detector has audible alerts but we think that they are not loud enough. When we tested the device in heavy city traffic it was tough to hear the alerts at times. The display is nice and bright and shows the band detected as well as signal strength.
You get 3 city modes and a highway mode with this Whistler model. The city modes do a reasonable job of cutting out false alerts but we did still experience a few. There is a periscope alert feature consisting of two LEDs that help to get your attention by flashing on and off.
When we tested this device we were pretty impressed with the range of around 1 to 1.5 miles in most weather conditions. The build quality of the detector was not that great though but for the money it was OK. It is easy to use and install and is fairly small measuring 4.4 inches by 1.4 inches by 2.8 inches and only weighing 5.4 ounces.
- Detects all radar bands and laser.
- Easy to use and install.
- Good value for money.
- An audible alarm is too quiet.
- Prone to false alerts
7. Cobra SPX 900 14 Band High-Performance Radar Laser Detector Review
Here is another reasonably priced radar laser detector from Cobra. It can detect 14 bands which are the 7 common radar bands, 6 laser signals, and a safety signal. The device offers all-around protection against laser signals. It also has a POP mode and VG-2 detection.
The Cobra SPX 900 14 Band High-Performance Radar Laser Detector also features a Spectre I feature which provides complete protection against Spectre I radar detector detection. The POP model was pretty effective and you get voice alerts and a display that has proudly mounted LEDs to indicate band and signal strength.
The highway and city modes work quite well with city mode helping to reduce false alerts. This is far from perfect though and we got a lot of false alerts. We found the range to be acceptable.
The biggest problem with the Cobra SPX 900 14 Band High-Performance Radar Laser Detector is that in our tests it failed to detect some sources. It is a little larger than some of the other devices at 3.7 inches by 2.4 inches by 1.3 inches but still pretty compact. It weighs around 8 ounces.
- Good band range.
- Voice alerts.
- The price is reasonable.
- Doesn’t detect everything.
8. Cobra ESR800 12 Band Radar Detector Review
Again this is a radar laser detector and not just a radar detector. This device will detect 12 different bands and provide audible and visual alerts. For laser signals, you get all-around protection for your car. This model also has a safety alert feature that warns you about hazards on the road such as emergency vehicles.
The audible alerts are a voice and these are loud and clear. The display on the Cobra ESR800 12 Band Radar Detector consists of protruded LEDs that indicate band type and signal strength. The display is very bright and easy to read.
As with most radar detectors you get city and highway driving modes. The city mode is supposed to prevent a lot of false alerts from occurring but this model falls down badly here. In our tests, we were picking up false alerts from everywhere and it was very distracting. We found the range to be around half a mile on the highway which is OK.
There is a useful auto-mute feature with this device which is convenient. You need it with all of those false alerts. This is an easy-to-use radar laser detector. It is larger than some of the other models at 7 inches by 4.5 inches by 2.2 inches. It weighs just under 9 ounces.
- Safety alerts are good.
- Voice alerts.
- Simple to use.
- A single sensor can only detect laser bouncing at the rear.
9. Rocky Mountain RMR-D540 Radar Detector Review
This device will detect the usual radar bands and laser signals as well. The manufacturer claims that this detector has advanced circuitry and it also has a SmartScan feature which makes signal detection faster and cuts down on the number of false alerts.
The Rocky Mountain RMR-D540 Radar Detector also has a Micro-Scan feature which the company claims enables the device to scan 2 to 4 times faster than other radar detectors. This helps with the detection of the super-fast POP radar.
As usual, there are city and highway modes and a nice touch is that it has a safety alert built-in to protect you from oncoming emergency vehicles and so on. When we tested this model we found the range to be reasonable but we were concerned that it didn’t detect a laser gun really close by and we got quite a few false alerts.
The Rocky Mountain RMR-D540 Radar Detector measures 3.6 inches by 2.2 inches by 1.1 inches and is heavier than some of the other units at 11.2 ounces. You will get a windshield mounting bracket as well as a power cord (coiled) when you purchase this device.
- Advanced electronic design.
- SmartScan feature.
- Good alerts and display.
- Did not detect everything.
10. Whistler CR75 Laser Radar Detector Review
Our final radar laser detector is the Whistler CR75 Laser Radar Detector. This device will give you all-around protection for your car including the sides and the rear. It can pick up signals from radar including X, K, and KA, and will also detect laser signals such as Laser Ally, Laser Atlanta Stealth, and LTI Truspeed 5.
This unit has voice alerts and the text-based display is reasonably clear showing the band and signal strength. There is a built-in false alert feature but we found this to be pretty ineffective as we experienced quite a lot of false signals in our tests. We also found that it didn’t pick up all of the signals that were around.
This device has long-range signal detection according to the manufacturer. We found the range to be reasonable but it wasn’t particularly that long. You can adjust the volume of the alerts and turn them off completely if you want to.
There is a POP mode with this model but we were unable to fully test this. The unit is fairly large measuring 6 inches by 3 inches by 8 inches and it weighs around 9.5 ounces. You do get a coiled power cord and a windscreen mount kit with the device.
- Radar and laser protection.
- Voice-based alerts.
- LED display is good.
- Did not pick up all threats.
How to use a Radar Detector
If you don’t use your radar detector properly then it will provide you with little protection if any at all. It is not just a matter of placing the device in your car and hoping for the best. The correct use of a radar detector is essential.
You need to really know your radar detector and what it’s telling you. A good radar detector will have different band alerts such as X band, K band, and laser. Then there is the signal strength. A quality radar detector should let you know how far away the speeding device is from the strength of the signal.
Normally a radar detector will have different modes that you can use. If you use the wrong mode where you are driving then this not only leads to a higher risk of false alarms but also to a reduction in the sensitivity of the radar detector.
The two most common radar detector modes are “city mode” and “highway mode”. If you are driving in built-up urban areas then you need to use city mode. Driving on the freeway you need to use the highway mode. Some of the more expensive radar detectors have an automatic mode.
Once you receive an alert from your radar detector you need to act as quickly as possible. You will not always know how far away a speed trap is so slow down gently. Avoid the temptation to slam on the breaks as this can bring even more unwanted attention.
Are Radar Detectors Legal for use?
The good news is that radar detectors are legal for use in most states. The only states where they are illegal are Washington D.C. and Virginia. The AAA (American Automobile Association) states that you can legally use a radar detector in a car or a light truck.
You cannot legally use a radar detector in a commercial vehicle in any state. In some states, it is not legal to use a radar jammer. These states are:
- California
- Texas
- Colorado
- Utah
- Illinois
- Tennessee
- Minnesota
- Oklahoma
- South Carolina
We have already told you that we do not recommend the installation of your radar detector in your windshield. But if you do this in some states you can get into trouble especially if you use a suction cup to mount the device. These laws are there to stop people from obstructing their view when driving.
How to Install a Radar Detector?
The correct installation of a radar detector is the most important factor. In the correct place, your radar detector will pick up the police radar signals fast and give you a chance to slow down to avoid a ticket.
It’s not a good idea to install a radar detector in the windshield of your car. If you do this then you will limit its ability to detect radar signals. Usually, a police officer will aim their radar gun at your license plate or headlamps. So you need to install your radar detector in a low position.
Wherever you mount your radar detector be sure that you have clear access to the controls for mode and volume. If the police pull you over and you have a radar detector clearly visible in your windscreen then you can get into more trouble.
You need to decide whether you are going to use batteries with your radar detector or hardwire it into your car. It will be more effective if you hardwire it but this is more work. You will need to run a power cable from your fuse box to the radar detector.
Always ensure that your radar detector is securely fixed. You will be using the controls to raise or lower the volume and to switch from one mode to another. An insecurely installed radar detector can slide away from its intended location and even suffer damage. Use the right mounting brackets to secure it in place.
Things to consider before buying the best Radar Detectors under $100: Best Buying Guide
The first thing to consider is the type of radar detector that you want. Here are two main types and sometimes there are combination devices available. The most basic radar detector is the digital model. These tend to be small and will provide protection against speeding tickets for those people who do not intentionally speed.
The next level up is a laser detector. These are useful for detecting lidar devices that an increasing number of police forces are using now. Laser detectors are more expensive than basic radar detectors and usually purchased by drivers that often speed and want the maximum chance of avoiding speeding tickets.
When you are looking at the different radar detectors under $100 pay careful attention to the features that they provide. Some radar detectors have a voice activation feature that you can use with your smartphone or Bluetooth.
Some radar detectors are GPS enabled. With this feature, the device can let you know about upcoming red lights, road construction problems, and speed traps. There are also radar detectors with personalization features so that you can change the brightness of the light indicators and more.
All radar detectors will have an audible alarm feature and some will have a display to view as well which provides more detailed information. Check to see if the radar detector has an automatic mode setting where it will automatically detect city or highway driving.
Frequently Asked Questions while Buying Best Radar Detectors Under $100 dollars: FAQ
Q1.Will all of the models detect laser?
Yes, all of the models featured in this review will detect laser signals
Q2. With a radar detector is it guaranteed that I won’t get a speeding ticket?
No, it isn’t. Even the highest-priced radar detectors can guarantee that you will not get a speeding ticket
Q3.What is the best make of radar detectors?
Uniden, Cobra, and Whistler all have good reputations in the market. It is not possible to say which one is the best.
Q4.Should I mount my radar detector on my windscreen?
Although most radar detectors come with windscreen mounts we don’t recommend this. We suggest that you mount the radar detector low in your car.
Q5.Are radar detectors less than $100 really any good?
Yes, we have shown you some good models in this review. The more expensive models are generally better though.
Final Words
We sincerely hope that you found this to be one of the best radar detector reviews under $100. Our aim is to provide you with all of the right information so that you can purchase the best radar detector for your purposes.
The features of a radar laser detector are nowhere near as important as the accuracy and performance. It is no use having a ton of features if it cannot detect threats well or just provides a lot of false alerts.
In this regard, the Uniden DFR3 Long Range Laser/Radar Detector is our top performer. It has a good range and will pick up almost anything to alert you of threats. It handles false alerts well and at under $100 it is a very good choice.
The Cobra RAD 350 Laser Radar Detector and the Cobra ESD7570 Radar Laser Detector are worthy of consideration as well. If you do not want the hassle of wiring in your radar detector or plugging it into your cigarette lighter then the Whistler XTR-450 Cordless Radar Detector is worth a look.