# Custom Running Intervals vs Fartlek

The clearest difference is update cadence: Fartlek at every 4 days against Custom Running Intervals's every 3 months. Custom Running Intervals's advantage is iOS requirement (16.0 vs 18.5). On price, ads, in-app purchases and device support there is nothing between them.

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

Custom Running Intervals ships an update every 3 months, Fartlek every 4 days. The most recent releases landed on November 3, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | Custom Running Intervals | Fartlek |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.0 (1 ratings)](https://appshunter.io/ios/app/custom-running-intervals/id1533333253/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 11 MB | 29 MB |
| Requires iOS | **16.0** | 18.5 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [John Mallonee](https://appshunter.io/developer/1520115384) | [Axis SA](https://appshunter.io/developer/1621529800) |

## What reviewers say

### Custom Running Intervals

[App page](https://appshunter.io/ios/app/custom-running-intervals/id1533333253)

Create custom running workouts with flexible intervals based on time or distance. Track progress, build training plans, and analyze past runs with detailed results. Your data is private and stored securely on your device or iCloud.

**Highlights:** Configurable time or distance intervals, Repeatable interval blocks, Training plan calendar, Historical run analysis, Apple Watch monitoring, iCloud synchronization, Data privacy

**Features:** Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Capabilities | $0.99 | one-time |


### 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 |


## Frequently asked questions

### Is Custom Running Intervals free?

Custom Running Intervals is free to download, with in-app purchases available.

### Is Fartlek free?

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

### Do Custom Running Intervals or Fartlek have ads?

Neither Custom Running Intervals nor Fartlek shows ads.

### Which is updated more often, Custom Running Intervals or Fartlek?

Custom Running Intervals ships an update every 3 months, and Fartlek every 4 days. Most recently, Custom Running Intervals was updated on November 3, 2026 and Fartlek on October 30, 2026.

---

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