A racing lap timer is more than just a fancy stopwatch: it tells you how fast your car is going around the track and can even help you become a faster, better driver.
Antuan GoodwinReviews Editor / Cars
Antuan Goodwin gained his automotive knowledge the old fashioned way, by turning wrenches in a driveway and picking up speeding tickets. From drivetrain tech and electrification to car audio installs and cabin tech, if it's on wheels, Antuan is knowledgeable.
ExpertiseReviewing cars and car technology since 2008 focusing on electrification, driver assistance and infotainmentCredentials
North American Car, Truck and SUV of the Year (NACTOY) Awards Juror
If you're into racing cars and want to level up your track game and go faster, a lap timer can make a big difference. Some car lovers are satisfied with the casual exhilaration of speed on a perfectly twisted road or the accomplishment of tackling a tough trail, and some are more driven to go faster.
You can make a car faster with more power or better suspension, but the best (and cheapest) performance upgrade that you can make is to the component between the seat and the steering wheel: you, the driver. One of the best tools to help you become a faster driver is a precise lap timer. While that can be as simple as setting a stopwatch at the start of each session, most dedicated racing lap timers use GPS technology to automatically mark each lap's beginning and end, separating the time for each and allowing the user to see how changes to your racing line and braking points affect your overall speed and RPM. The best examples also log and save your sessions digitally -- often along with vehicle performance test data or video -- for review later.
It can be difficult for a novice to look at GPS data and lap times and know exactly how to go faster. Ideally, this is where an experienced driving coach comes in to help make heads or tails of the information. However, if you can't find human help, a new class of digital track coaching devices may be able to help. These devices use a combination of artificial intelligence and predictive lap timing to analyze the logged data and make suggestions, often in real time on the track, to improve your speed for each subsequent lap.
The Aim Solo 2 is one of the most recommended lap timers for amateur racer and high-performance driving events -- both novices getting serious about racing and seasoned enthusiasts -- and with good reason. The Solo 2 features an easy-to-read 3-inch display with color customizable backlight and large, legible text. The unit is about as plug-and-play as they come: Mount it, power it and head onto any of more than 2,000 preloaded tracks to have your laps tracked and logged via precise GPS/Glonass with 10Hz resolution.
In addition to automatically tracking your current lap time number, the Aim Solo 2 can display split times and predictive lap times (I'll explain the difference in a moment). The Solo can also be used for performance benchmarks outside of the circuit for point-to-point races, drag races or just to get precise 0-to-60 times. When you're done driving, logged timing, GPS, accelerometer and gyro data can be recalled either on the device itself or on a PC via Wi-Fi.
At just $400, the Aim Solo 2 offers essentially everything you need to get up and running with precise timing on and off the track and nothing that you don't. More experienced drivers with a bit more to spend should also consider the $700 Aim Solo 2 DL; the more expensive model upgrades with ECU connectivity allowing it to also display and log data from your car's onboard sensors and enables useful features like a programmable shift light. The modular DL can also be upgraded to log multiple external sensors and even connect to Aim's Smartycam system. Solo 2 can be used in all of your performance situations: hill climbs, regularity, speed races in closed circuits, and point to point races. It provides powerful data review and records all of the data you need while racing such as the sector times. You just need the right cables to connect the Solo 2 to your car.
The sweet spot in Racelogic's Vbox line of racing monitoring systems, the Performance Box Touch is also one of the brand's newest models. It's priced ($680) just below the Aim Solo 2 DL, but without the ability to connect to your car's ECU or external sensors, its feature set is closer to that of the Aim Solo 2.
However, the PBT isn't without advantages of its own. The unit is built around a full-color 4.3-inch display that is not only larger, but more customizable than the Aim units' -- not that you should be spending too much time admiring the screen while tearing around the track. Vbox also claims that its proprietary Delta-T and Delta-V predictive lap timing algorithms are more accurate, making the PBT potentially a better learning tool.
Aim's Track Day kit bundles the Solo 2 DL with its Smartycam HD 2.1 camera. The two devices can be hung from your windshield on the same double-bracket suction cup mount, giving you a simple way to monitor and record driver and vehicle performance data with video. That's in addition to all of the flexibility and upgradability that make the DL model such a fantastic choice on its own.
If there's one weak spot, it's that the SmartyCam isn't very cinematic. It only captures at 720p and 30 frames per second, plus you'll have to choose between a narrow (67-degree) or wide (84-degree) field of view at the time of purchase. That's lower resolution, frame rate, FOV and overall image quality than a GoPro, the current gold-standard for action cameras. So, if visual fidelity is paramount, it may be worth mating a 5K GoPro Hero 9 with the Solo 2 DL and learning to use third-party editing software to manually overlay your logged data.
However, the Solo 2 DL and Smartycam combo are unmatched in their functionality and ease of use. The camera can automatically overlay any of the myriad of data captured by the Solo 2 DL -- like a G-force meter, a live track map, virtual gauges and more -- onto its captured footage, making it easy to share your on-track exploits and victories without having to learn to edit video. Plus, it automatically starts recording along with the Solo 2 DL as soon as you hit the track, so you'll never have to worry about forgetting to hit record -- or being unable to reach because of a restrictive harness.
Here's the catch: We could only find the Track Day Bundle on Aim's UK-based website, so if you don't want to pay in pounds and ship internationally, you'll need to order the Smartycam and the Solo 2 DL separately at the links below and connect them on your own. The Smartycam is currently unavailable on Amazon.
About the size and shape of a small radar detector, the Vbox Sport packs in all of the high-resolution GPS tracking and precision lap timing of the Performance Box Touch, but without the touchscreen. In fact, there's no screen at all! While this may seem like a downgrade, the headless setup has its advantages.
For starters, no screen means nothing to distract you while ripping it up on the track. GPS, gyro, accelerometer and timing data are stored on an SD card for retrieval and analysis later, so you won't be tempted to look away from the road. The compact size also allows for more flexible mounting, you can tuck it into the corner of the windscreen, out of your line of sight. Plus, the entire unit is waterproof and fairly lightweight, which makes it also ideal for use on motorcycles, boats, ATV and side-by-sides, bicycles, large R/C craft and planes or pretty much anything you can mount (or zip-tie) the Vbox Sport to.
And if you ever need a screen, Bluetooth connectivity means that you can still view live lap times or review logged data on a paired smartphone in the Racelogic app or any of the recommended third-party lap timer apps below.
Garmin's Catalyst can and does function as a lap timer, displaying your current lap and split times on its 7-inch color touchscreen and automatically logging your on-course GPS/Glonass position with 10Hz resolution and accelerometer data whenever you hit the track. It also captures video with a 1080p, 30fps camera. However, the Catalyst's greatest trick takes place after you return to the pit.
At the end of each session, the Catalyst uses artificial intelligence and a built-in sensor to analyze the captured data and video, remixing your best segments into a True Optimal Lap -- a video representation of the fastest lap possible based on the track, the vehicle and your skill level. This, according to Garmin, is better than a split time because it not only tells you how much faster you're getting, but how to be faster by suggesting where improvements can be made.
On subsequent sessions, Catalyst can even give audio feedback in real time to help you achieve the True Optimal Lap -- hints like apex sooner, brake later or good segment -- which can be played through the device's internal speakers, the car's stereo system or even a Bluetooth headset or comms system. Heavy-duty mounting bracket securely positions Catalyst inside the cockpit. Even better, as you improve, so does your True Optimal Lap. The Garmin can also store multiple profiles for different drivers and vehicles.
So why isn't this the best overall lap timer? As good as the Catalyst is at coaching novice to intermediate racers, it's missing a few features. For starters, the $1,000 Catalyst doesn't connect to the car's ECU like the Aim Solo 2 DL and can't log external sensors. Plus, it's only able to be used for circuit racing and HPDEs; point-to-point racing, drag racing and 0-to-60 testing is not currently supported.
Even with these shortcomings, the Garmin Catalyst is -- short of an experienced human coach riding shotgun -- the best way to get faster on the track and will grow along with your skill cap.
TrackAddict boasts an extensive feature set that can transform the iPhone or other smartphone in your pocket into an impressive racing recorder. The app takes advantage of the phone's GPS antenna to record track position and display lap time, split time, predictive time and more with an easy-to-use interface. It can also record HD video using the phone's camera and overlay data and graphics for sharing.
In addition to lap timing for circuit racing, TrackAddict features modes for point-to-point races -- useful for autocross or rallying -- drag racing and even a low-speed 4x4 trails mode that logs pitch and roll information. Plus, it's free with in-app purchases for only the most advanced features.
TrackAddict is also able to ingest precise GPS data from an external receiver -- like the Vbox Sport -- for more precise high-resolution positioning than the phone's antenna can offer and can even connect to Bluetooth adapters to log data from your car's ECU -- such as engine speed, throttle position and more.
For a long time, Harry's Lap Timer ruled the roost as the go-to smartphone lap-timing application. It's extremely flexible, able to log and display a wide gamut of racing data, and very easily customizable in how that data is displayed. I personally used versions of Harry's for many years before switching to TrackAddict's more casual streamlined interface, but with smarter features like laps to pit -- which calculates how many laps you've left before needing to refuel -- and better predictive timing, Harry's is overall the better app.
It's also the more expensive app with three versions to choose from. For most, the base $9 Rookie app is good enough to get started timing laps, but to match the level of TrackAddict's functionality (with video recording) requires an upgrade to the mid-spec Petrolhead product for $20. The flagship Grand Prix version ($28) boasts truly unique features like the ability to compare two video laps side-by-side and even remote control multiple GoPro and Sony cameras. Even at its priciest, the cost is reasonable for what you get, but it's hard to compete with free.
Most lap timers need to be suction-cupped to the windshield or bolted to the dashboard, but the instrument cluster is the most streamlined place to monitor your performance from the driver's seat. Almost every car already has an instrument cluster, but an aftermarket replacement means you're not necessarily stuck with the factory-installed gauges.
Aim MXG 1.2 Dash Data logger features a 7-inch TFT display -- the largest Aim offers -- and is designed to function as a full-digital racing instrument cluster. Pulling data from your car's ECU or multiple external digital or analog sensors, it can display speed, a tachometer with shift light, temps, oil pressure and more. Plus, with its included GPS antenna and internal accelerometer, the MXG can automatically track and display lap times and split and predictive times with all of the fidelity matching or exceeding the Solo models, storing racing data on an SD card for post-race retrieval and analysis. And like the Solo 2 DL, the MXG is compatible with Aim's Smartycams.
For all but purpose-built race cars, a cluster replacement is complete overkill and a little impractical, but the Aim MXG 1.2 is the most no-compromise lap timer flex. This item is out of production, so it is a little harder to get your hands on one.
Matching plug-and-play simplicity with extreme precision, the Aim Solo 2 (or the upgraded Solo 2 DL) is the best GPS timer for most racers, novice to experienced, for all types of racing.
Best lap timer runner-up
Performance Box Touch
The Performance Box Touch is pricier than its primary competitor, but also boasts a color screen and the promise of better predictive lap timing.
Best lap timer if money is no object
Solo 2 DL / Smartycam HD 2.1
This Track Day Kit can automatically log lap times, monitor vehicle systems and sensors and automatically overlay that data onto an HD video to analyze and share.
Best screenless lap timer
It lacks a screen, but the Vbox Sport still logs timing and location data with extreme precision. Plus, its compact, waterproof design makes it ideal for use on boats or even R/C craft.
Best track driving coach lap timer
The Garmin Catalyst not only logs your laps with HD video and precise GPS, but its AI software also analyzes the data for you and makes suggestions that help you go faster next round.
Best lap timer app
TrackAddict is a streamlined lap timer app that makes it easy to get setup recording sessions at the track. Most importantly, it's free to get started.
Best lap timer app runner-up
Harry's Lap Timer Petrolhead
Harry's Lap Timer is a longstanding favorite. It's more expensive than TrackAddict and it's a bit more complex, but its enhanced analysis tools make it a better pick for seasoned drivers.
Best dashboard replacement lap timer
Replacing your entire instrument cluster with a lap timer/data logger is probably overkill, but for purpose-built race cars (and trucks) the Aim MXG is the best in the business.
What should a good lap timer do?
The obvious answer is that a lap timer should accurately measure, separate and store your lap times while you race around a track, but it's a skosh more complex than that. For starters, you'll be too busy driving to manually mark your laps, so a good lap timer should make use of GPS to automatically track when you cross the start-finish line.
The best lap timers will store your laps for analysis and comparison with future sessions and should also provide some sort of performance feedback while on the track. This could be as simple as displaying a split time or more complex.
What to look for in a GPS lap timer?
The more accurate the device's positioning, the more accurate your measured times will be, so a high-quality GPS antenna is paramount. Look for a receiver compatible with the Global Navigation Satellite System, which combines tracking on both the GPS and GLONASS satellite constellations for the most precise positioning.
At 80 mph, a car travels around 117 feet every second. So, for fast moving vehicles on a race track, refresh rate (measured in hertz) for positioning data is just as important as accuracy. I've seen specialty GPS trackers reach as high as 16 to 20Hz, but most good lap timers will have a refresh rate of around 10Hz. Extremely cheap timers (or older smartphones) can dip as low as 1 to 6Hz, which causes inconsistent detection of the start/finish line and inaccurate timing.
Speaking of the finish line, a good lap timer built for racing applications should have built-in location data for popular racetracks. That doesn't mean you'll be looking at a map, but having the same position for the finish line (as well as the same starting points for track segments) makes it easier to compare and share your time and performance with other drivers.
Though not strictly necessary -- as with the screenless Vbox Sport -- a large, easy-to-read display is very nice to have. Ideally you'll be watching the grid and not the clock once the green flag drops, but big, legible numbers means that you won't have to squint to glance at your split. Along that same line, a good lap timer should also be a data logger, since it's much safer and easier to look at lap data from the pits.
What is predictive lap timing?
A split time is the difference between your pace on your current lap and that of your previous best. Race tracks are broken up into segments and splits are usually calculated at the end of each one. So if you get to the end of the first segment a second sooner than last time, your split is minus 1 second. However, if you lose two ticks on the next segment, its split will be plus 2 seconds and, at the end of the lap, your total split will be plus 1 second. Split timing aids in finding the sections of the track that are giving you the most trouble and can help you see how adjustments affect your overall lap time.
Predictive timing -- sometimes called delta timing -- takes that concept a step further, calculating in real time how your current performance stacks up with your previous best and estimates of how long your current lap will take based on changes to your racing line, acceleration and braking. This can be as simple as an LED that turns green when you're faster and red when slower, or a live updating lap time prediction. If, for example, braking a touch earlier in a specific bend results in a faster exit speed, you may see your predictive time drop instantly. This makes it easier to pinpoint small improvements that can be lost waiting to complete a lap or even the current segment.
What is a driving coach?
Experienced drivers are able to look at their lap times, maybe compare notes with other drivers and see where improvements can be made. However, novice racers may need the help of a driving coach to make heads or tails of the data. While there is no replacement for an experienced human riding shotgun, digital driving coaches like the Garmin Catalyst or the Apex Pro Driving Coach can be extremely helpful.
Digital coaching is like predictive lap timing on steroids, going beyond just showing when you're faster to telling you how to get faster. The Catalyst combines GPS, accelerometer and camera data to track you. At the end of your session, the best segments of multiple laps are combined into a True Optimal Lap -- a hypothetical best lap based on your performance.
This, in itself, isn't particularly special -- many lap timers can calculate an optimal lap -- but the difference is that the Catalyst takes that data and uses it to give feedback on your next driving session. The AI will give audio prompts and hints telling the driver to, for example, brake later here, apex sooner there, or stay on the gas just a bit longer. The more laps you complete, the better the suggestions returned by the Catalyst. Additionally, because the optimal lap is based on your best segments, the driving coach also grows with your skill cap.
How do you mount a lap timer?
Most standalone racing lap timers will ship with some form of suction-cup mount, but not always. Make sure to check before you buy. A suction cup is the easiest mounting option, allowing the device to be attached to the windshield like a GPS navigator or radar detector and then easily removed at the end of your lapping session. Windshield mounting also gives a lap timer's GPS antenna the clearest view of the sky for the best satellite positioning accuracy.
A more secure mounting option is a bolt-in dashboard bracket. This semipermanent mounting method is more secure than a suction cup -- especially in the event of a collision -- and has the added benefit of keeping your windshield clear of obstructions. You may have to modify or drill into your dashboard to bolt it in, and you'll want to make sure that your chosen mounting position doesn't block the GPS antenna.
For motorcycle and powersports applications, a handlebar mount can be used to hold your lap timer securely in place. Aim even offers padded bar mounts for its Solo 2 and Solo 2 DL models. Full instrument cluster replacements like the Aim MXG are the most time and labor intensive installations and should only be attempted if you absolutely know what you're doing.
Things to consider about lap timer apps
The most cost-effective way to start timing your laps today is to download a lap timer app and simply use the phone that's already in your pocket. Apps like Harry's Lap Timer and TrackAddict offer feature sets that rival the best dedicated GPS lap timers on this list, but there are a few catches.
The performance of a lap-timer app is highly dependent on your phone, since it's the handset's GPS and accelerometers doing the heavy lifting. Newer devices are usually up to the task, but an older phone can be to blame for an inconsistent and frustrating lap-timing experience. There are a few things you can do to give your phone a leg up.
First, you'll need to budget for a dashboard or windshield mount; your pocket or a cup holder won't do. The phone will need a clear view of the sky to give its GPS antenna the best shot at accurate positioning. Look for a firm, stable mount -- not one of those flexible goosenecks -- that locks into place and allows the accelerometers to more precisely measure G-forces, ensures that the handset won't go bouncing around the cabin when you hit a bump and may even let you use your phone's camera to record video of your laps. As an added benefit, you can also use the mount when navigating home at the end of the day.
A mobile phone's GPS is designed with power management and navigation in mind, which can mean compromising on refresh rate. Many older phones can have GPS refresh rates as low as 1 to 6Hz, which is fine for turn-by-turn directions but isn't the best for precise, high-speed measurement. That refresh rate may drop even lower -- below even 1Hz -- to help save power when the screen is off or the battery is low, even on relatively new phones. So, you'll want to keep your phone plugged in and awake during your laps.
If your phone's not cutting it but you don't want to make the jump to a dedicated timer, consider augmenting your device with an external Bluetooth GPS antenna -- like the Vbox Sport or the Garmin GLO 2 -- to add more precise, high-refresh positioning. Both Harry's and TrackAddict support dozens of third-party receivers, but you'll want to double-check for compatibility with your phone's OS. You can also add an adapter that connects to your car's diagnostics port to allow the app to capture ECU data, such as engine speed, throttle position and more.