# Fartlek vs OnTrack Run Interval Timer

The clearest difference is update cadence: Fartlek at every 4 days against OnTrack Run Interval Timer's fortnightly. OnTrack Run Interval Timer's advantage is iOS requirement (16.2 vs 18.5). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Fartlek sells 3 in-app purchases, starting at $1.99 per 7 days and OnTrack Run Interval Timer sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Fartlek ships an update every 4 days, OnTrack Run Interval Timer fortnightly. The most recent releases landed on October 26, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Fartlek | OnTrack Run Interval Timer |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 4 days** | Fortnightly |
| Size | 29 MB | 2 MB |
| Requires iOS | 18.5 | **16.2** |
| Devices | **iPhone, Apple Watch** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Axis SA](https://appshunter.io/developer/1621529800) | [Jekal Ik](https://appshunter.io/developer/1860824839) |

## What reviewers say

### Fartlek

[App page](https://appshunter.io/ios/app/fartlek-interval-run-timer/id6752724674)

**Features:** Apple Watch app

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Plan | $1.99 | per 7 days |
| Monthly premium | $4.99 | per month |
| Yearly Premium | $29.99 | per year |


### OnTrack Run Interval Timer

[App page](https://appshunter.io/ios/app/ontrack-run-interval-timer/id6757700812)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium - Background Mode | $0.99 | one-time |


## Frequently asked questions

### Is Fartlek free?

Fartlek is free to download, with in-app purchases available.

### Is OnTrack Run Interval Timer free?

OnTrack Run Interval Timer is free to download, with in-app purchases available.

### Do Fartlek or OnTrack Run Interval Timer have ads?

Neither Fartlek nor OnTrack Run Interval Timer shows ads.

### Which is updated more often, Fartlek or OnTrack Run Interval Timer?

Fartlek ships an update every 4 days, and OnTrack Run Interval Timer fortnightly. Most recently, Fartlek was updated on October 26, 2026 and OnTrack Run Interval Timer on October 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*