iPhone Screenshots


iAccel is a performance meter designed to test the acceleration and braking performance of your vehicle. In use it displays a series of gauges to monitor performance and a continual graph of selected parameters. When performing a test the results can be displayed on screen and are stored in a CSV file for easy export if further analysis is required.

In addition to brake testing, 0-30 and 0-60 mph acceleration tests are available together with their metric equivalents. Standing ¼ mile acceleration, standing 400 m, 0-80 mph and 0-120 km/h tests together with EDR and Crash modes are available as an upgrade to the Pro version. iAccel also has a continual recording mode which simply records the data to a CSV file received while the device is operating. To avoid running of of space continuous recording is limited to 5 minutes in the Pro version and 20 seconds in the Free version. If you run over this time, the device will continue to record the last 5 minutes (20 seconds) of data and delete older data unless the AutoStop option is selected in the settings.

A calibration check feature is also available in the Pro version so you can check and record to a file the accuracy of the accelerometers.

To use the app, your iPhone should be mounted in the vehicle with the long edge of the phone perpendicular to the direction of travel. The device doesn't have to be perfectly level, approximately level is fine.

Drive to the area where the test is to be performed and start the app. This launches the test screen and automatically calibrates the device to the gradient at that location. The Reset button can also be used to recalibrate the device at any time and is best performed when the vehicle is stationary. This avoids any bumps in the road distorting the calibration. You can change the type of test you want to perform using the Select Test screen which can be accessed by pressing the Menu button.

For Brake and Acceleration tests press the Arm button when you are ready to begin the test and perform the test. You can press the Arm button at any time, even when the vehicle is in motion. The results will be displayed automatically once the test is complete and includes two seconds of data prior to the start of the test and a short time after the test has finished. The limits of the test are highlighted on the result graphs.

For Continuous type tests, press the Start button to start recording and press the Stop button to stop. Continuous test results are not displayed automatically but results can be displayed from the Files options accessed by pressing the Menu button.

For ease of use, double tapping the Speedometer duplicates the effect of pressing the Start / Stop button. Double-tapping the left-hand gauge duplicates the Day / Night button and double tapping the right-hand gauge duplicates the Reset button.

Tapping on the graph, cycles the display between acceleration, speed, orientation, rate of rotation and magnetometer.

More detailed information on the operation of iAccel is available from the Information page in the app.

The app uses a combination of GPS, accelerometer and other sensors and is only accurate when the device is operated correctly and all sensors are receiving suitable signals. Please note that continued use of GPS can dramatically decrease battery life.

This app is designed for use off-road and any performance testing should only be performed off the public road network. At all times you must comply with all traffic regulations applicable to your location. J Neades can accept no liability for any injury, loss or damage which may occur while using this app.

What’s New

Version 1.7

Addition of alternative gauge options. Will now display altimeter or compass in addition to power and acceleration
Addition of option to check calibration (Pro only)
Addition of Event Data Recorder (EDR) mode to record previous 60 s of data (Pro only)
Addition of Crash mode to easily record raw data (Pro only)
More effective auto-levelling to determine device orientation during use
Internal accelerometer calculations now include position of device within the vehicle
CSV output now includes raw accelerometer data and magnetometer output
Rotation data consistent across entire test with CSV OffsetX value showing current change in pitch angle to facilitate easier post-incident analysis
Addition of magnetometer graph display
GPS indicator includes current precision
Various other bug fixes and performance enhancements


Joseph G Neades
1.6 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad 2 Wi‑Fi + Cellular, iPad (3rd generation) Wi‑Fi + Cellular, iPad (4th generation) Wi‑Fi + Cellular, iPad mini Wi‑Fi + Cellular, iPad Air Wi‑Fi + Cellular, iPad mini 2 Wi‑Fi + Cellular, iPad Air 2 Wi‑Fi + Cellular, iPad mini 3 Wi‑Fi + Cellular, iPad mini 4 Wi‑Fi + Cellular, iPad Pro (12.9‑inch) Wi-Fi + Cellular, iPad Pro (9.7‑inch) Wi‑Fi + Cellular, iPad (5th generation) Wi‑Fi + Cellular, iPad Pro (12.9‑inch) (2nd generation) Wi‑Fi + Cellular, iPad Pro (10.5‑inch) Wi‑Fi + Cellular, iPad Wi‑Fi + Cellular (6th generation), iPad Pro (11‑inch) Wi‑Fi + Cellular, iPad Pro (12.9‑inch) (3rd generation) Wi‑Fi + Cellular, iPad mini (5th generation) Wi‑Fi + Cellular, iPad Air (3rd generation) Wi‑Fi + Cellular, and iPad (7th generation) Wi‑Fi + Cellular.


English, Dutch, French, German, Greek, Italian, Japanese, Portuguese, Russian, Spanish, Swedish, Thai, Turkish

Age Rating
In-App Purchases
  1. iAccel Pro $2.99


  • Family Sharing

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

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