Harry's LapTimer is the advanced tool for car enthusiast. It records all types of sensor data provided by your iPhone/iPod/iPad (or external sensors), combines them, and makes them available to optimize your drive. Over time, you will get insights on your car and in your driving, not known before.

LapTimer offers more than 1000 predefined tracks world wide. With its assistants, it is extremely easy to setup - just click your track and drive. It fully automates your lap timing using GPS, and presents the results to all kinds of media.

You are not limited to track driving only. For example, you may define your home and working locations as a 'track', collect statistics on different ways chosen, and analyze / optimize the time used every day.

Want to show your drive to your friends? LapTimer generates beautiful in car video recordings with all kinds of data overlaid, ready to be presented - e.g. on youtube. Even without video, recorded data can be analyzed using purpose designed views, making it easy to analyze and improve your driving performance.

Using online racing, you can use LapTimer in competition. LapTimer offers a Hall of Fame, allows watching you and your friends on track - all in real time. Compare your sector times, braking / acceleration points, and learn from each other.

You can start with your plain iPhone in the beginning and add external GPS and OBD II sensors later, step by step, and as you need it. LapTimer itself comes in three different editions: LapTimer Rookie is the entry level with all you need for lap timing; LapTimer Petrolhead is the advanced version including lots of video features, and LapTimer Grand Prix is the edition for professionals including Multi Cam recording, and advanced sensor and analytics functionality.

Please note that functionality depends on your device, the LapTimer edition chosen, and sometimes even external sensors added (like OBD II). Please visit our web page to get the full story. All edition can be upgraded later, all editions come with native iPhone and iPad support.

There are quite expensive stand alone solutions for track days available. Be smart and own the leading edge tool simply by using your iPhone and LapTimer. Besides the professional area, there is no known solution that offers more functionality than LapTimer does - across the market. As our ambition is to offer the best tool, LapTimer is enhanced continuously.

Please visit for detailed information on versions, FAQs / documentation, in depth technology background information, online racing, and supported device configurations. Join our user community on to be involved in future development - all with first class support.

What's New

Version 22.0.4

Version 22.0.4 is a bug fix release addressing issues reported.

Welcome to version 22 of Harry's LapTimer. This major release has a special focus on faster and broader sensor support. As a special feature, you can define the data storage rate independent from sensor update rates. As an example, even the internal GPS can give you smooth 10 Hz recordings now. A detailed list of changes is available below. Please report any issues directly to or post on

Sensor Handling
- Variable recording rates using splined interpolation (e.g. 5 or 10 Hz)
- Full brake pressure support
- Refactored existing code to allow flexible configuration
- Automatic bus type detection, all optimizations are done automatically
- Support for custom PIDs, formula based evaluation (experimental)
- Added support for physical ECU addressing, major speed improvement
- Improved OBD debugging support
- Further update rate improvements
- End to end sensor data queuing minimizing real time effects
- Support for extended channels: gear, odometer, brake pressure, individual
wheel speed, steering wheel angle and rate - requires scripting or
custom PIDs
- Support for ReDrive sensor
- Support for Cycling Speed and Cadence (CSC) sensors
- Disabled generic sensor configuration
- Support for VC601 TPMS sensors (experimental)

User Interface
- Lots of User Interface refinements
- Hall of Fame filtering by Group
- Further iPhoneX layout improvements
- Edmunds support removed (discontinued by Edmunds)
- Support for low rpm vehicles
- Precision wheel circumference settings
- Added Smart Bike section to Vehicle Details

- Added brake pressure to video overlays

- Update to watchOS 3.0 (no functional changes)
- Added entries for HERO6 BE and HERO 2018 [GrandPrix]

Special fixes
- Fixed "decoder busy" issue
- Avg. speed calculation uses standard configuration track length
- Full session video overlays improved

Optimizations, fixes, and minor improvements all over the place.

Ratings and Reviews

3.3 out of 5
12 Ratings
12 Ratings

Incredible application, even better customer service


Been a user for few years and it’s quite honestly one of the best lap timer solutions (and not just among mobile apps). Other professional setups will cost you over $1000 when you factor in hardware but this app will fine on its own give you nearly same level of data acquisition. Best of all is Harry’s dedication to the community. He personally responds to all troubleshooting requests despite the majority of questions being repeat asks already covered in his FAQ and provides regular feature updates to the software. Anyone complaining about user difficulty didn’t spend the 5 mins to read the user guide.

Unbelievably great

Austin Johnny

I’m completely blown away by the features and functionality of this app, and the documented support. There are so many things you can do with it, an incredible array of supported accessory devices, and with all the complexity available there is documentation and online support that makes it easy to work with. Best value it track software out there.

Not accurate


So I did a track day at Thunderhill and while I wasn’t expecting to break any track records, I was expecting accurate information. It measured my top speed on average 7mph slower than my car instrumentation. I compared to what my GoPro was filming, it was timing my laps over 8 seconds on average slower. I can’t explain how disappointed I was. I guess you get what you pay for. Buyer beware that if you want accurate information, this is not the app for you.

Developer Response

On speed: car dashboards will always display a too high speed, typically 2 to 5%. This is due to legislative requirements (dashboard gauges must never display a too low value). Opposed to your gauges, GPS measured speed is super accurate for constant speeds (like on a highway). Compare values shown here to understand how optimistic your dashboard is. True is, that speed peaks are not captured well by low update rate GPSes like the one built into your iPhone. So in case you want to make sure you get precise speed in all situation, opt for one of the 10 Hz GPS devices shown on

Provided you have good GPS accuracy, times will be pretty accurate. For the internal GPS, expect an accuracy of +-0.05s. Make sure you mount your iPhone like shown in illustration #3 of LapTimer's Quick Reference. Accuracy will be low if you wear the iPhone in your pockets or on the co-driver's seat. It should be clear that bad accuracy makes it impossible for an app to understand what is going on. In case you are still curios about your lap time, export your lap to .HLPTRL and send it to We can analyze data after the fact and provide you with an expected lap time range you achieved in reality.


Harald Schlangmann
83.3 MB
Requires iOS 9.3 or later. Compatible with iPhone, iPad, and iPod touch.
English, French, German, Italian, Japanese, Simplified Chinese, Spanish, Traditional Chinese
Age Rating
Rated 4+
© Harald Schlangmann
In-App Purchases
  1. Grand Prix Upgrade $9.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like