Comparison

Harry's LapTimer Grand Prix vs Simple Interval Timer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Harry's LapTimer Grand Prix

This app records and analyzes sensor data from your device to help you optimize driving performance. It offers automated lap timing, video recording with data overlays, and real-time online racing features. Track your progress on over 1300 predefined tracks or everyday routes.

Highlights
  • Sensor data recording
  • Automated lap timing
  • In-car video recording with data overlay
  • Real-time online racing and competition
  • Track and everyday route analysis
  • External sensor integration (GPS, OBD II)
Features
Read full description

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 1300 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 Petrolhead and above 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, Health Kit integration, 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 http://www.gps-laptimer.de for detailed information on versions, FAQs / documentation, in depth technology background information, online racing, and supported device configurations. Join our user community on http://www.gps-laptimer-forum.de to be involved in future development - all with first class support.

About

Simple Interval Timer

This app provides a straightforward interval timer for various training types like running, cycling, and HIIT. Customize sets, action, and break durations for a personalized workout experience. It runs in the background and saves recent configurations.

Highlights
  • Customizable sets, action, and break durations
  • Plain and simple design
  • Saves last 5 configurations
  • Runs in the background
  • iOS screen dimming prevention
  • Apple Watch integration with heart rate monitoring
Features
Read full description

Simple Interval Timer (SIT) can be used for any kind of interval training, such as running, cycling, HIIT sessions (including Tabata method), stretching, etc. SIT is exactly what you would expect. An interval timer, which is easy to set up and use. It features a nice plain design, with no unnecessary controls. Adjust Number of Sets, Action and Break duration to your needs and you are ready to go! On the iOS an extra switch control allows you to prevent the screen from dimming. SIT remembers the last 5 configurations you have used. Swipe left across the Settings screen to switch to another configuration. SIT can run in the background, while you are playing music, watching videos or doing anything else on your iOS device. SIT Watch features the same simplicity as the iOS app while offering the same functionality, plus it will measure your heartbeat during the workout sessions. The recordings will be available in the Apple's Health app. SIT Watch runs independently of the phone, so no need to have your phone around during your workouts (although you will need your phone during the very first time you launch SIT watch). SIT lets you avoid any tedious set up and focus on your training!

Screenshots

Harry's LapTimer Grand Prix4 screens
Simple Interval Timer4 screens

Verdict

The call

The clearest difference is price: Simple Interval Timer at Free against Harry's LapTimer Grand Prix's $27.99. Simple Interval Timer also leads on rating (4.9 vs 4.0) and review sentiment (85% vs 58%). Harry's LapTimer Grand Prix's advantage is in-app purchases (none vs 4) and ads (none vs shown). On monetization model and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Simple Interval Timer is free to download; Harry's LapTimer Grand Prix costs $27.99 up front. Simple Interval Timer sells 4 one-off in-app purchases. Harry's LapTimer Grand Prix asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Simple Interval Timer holds the better App Store score, 4.9 against 4.0. That said, the two scores are not equally well evidenced: Simple Interval Timer has 5.4K ratings behind it against 80, so its average is the more settled of the two. Written reviews point the same way: 58% of Harry's LapTimer Grand Prix's written reviews are positive against 85% of Simple Interval Timer's.

UpkeepUpdate frequency

Harry's LapTimer Grand Prix ships an update every 2 months, Simple Interval Timer every 8 months. The most recent releases landed on September 21, 2026 and September 25, 2026 respectively.

Scorecard8 real differences · 2 level
Harry's LapTimer Grand Prix versus Simple Interval Timer: the parameters behind the verdict, then further details
ParameterHarry's LapTimer Grand PrixSimple Interval Timer
Price$27.99Free — better
Rating4.0 (80 ratings)4.9 (5.4K ratings) — better
Positive reviews58.2% of reviews84.7% of reviews — better
Number of ratings805.4K — better
Update frequencyEvery 2 months — betterEvery 8 months
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationFreemiumFree with in-app purchases
DevicesiPhone, iPad, iPod, Apple Watch — betteriPhone, iPod, Apple Watch
Requires iOS12.0 — better14.5
Further details — not scored
Size81 MB10 MB
Age rating4+4+
DeveloperHarald Schlangmann0FF

Customer experience

Harry's LapTimer Grand Prix

All ratings80 ratings
Positive75.0%
Neutral6.3%
Negative18.8%
Written reviews98 reviews
Positive58.2%
Neutral7.1%
Negative34.7%

Simple Interval Timer

All ratings5,444 ratings
Positive97.6%
Neutral1.2%
Negative1.2%
Written reviews398 reviews
Positive84.7%
Neutral4.5%
Negative10.8%

Bugs and requests

Harry's LapTimer Grand Prix

Not enough reviews yet to summarise bugs or requests.

Simple Interval Timer

Reported bugs

3 issues
  • Timer stops working when screen is locked
  • Countdown beeps not syncing with timer
  • Interval times not accurately tracked

Requested features

4 requests
  • Ability to name and delete saved configurations
  • More granular interval time settings (e.g., 1-second increments)
  • Stronger haptic feedback on Apple Watch
  • Integration with workout tracking apps

In-app purchases

None

Harry's LapTimer Grand Prix

No in-app purchases

4 purchases

Simple Interval Timer

One-time4
  • Espresso$0.99
  • Americano$1.99
  • Ad-free version$2.99
Show 1 more
  • Caramel Cappuccino$2.99

Questions

Is Harry's LapTimer Grand Prix free?
Harry's LapTimer Grand Prix costs $27.99, with no in-app purchases.
Is Simple Interval Timer free?
Simple Interval Timer is free to download, with in-app purchases available.
Which has better reviews, Harry's LapTimer Grand Prix or Simple Interval Timer?
Simple Interval Timer is rated higher. Harry's LapTimer Grand Prix averages 4.0 out of 5 from 80 ratings, while Simple Interval Timer averages 4.9 from 5.4K ratings.
Do Harry's LapTimer Grand Prix or Simple Interval Timer have ads?
Simple Interval Timer shows ads; Harry's LapTimer Grand Prix does not.
Which is updated more often, Harry's LapTimer Grand Prix or Simple Interval Timer?
Harry's LapTimer Grand Prix ships an update every 2 months, and Simple Interval Timer every 8 months. Most recently, Harry's LapTimer Grand Prix was updated on September 21, 2026 and Simple Interval Timer on September 25, 2026.

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