# onTrack vs Hydra

The clearest difference is ads: onTrack at none against Hydra's shown. Hydra's advantage is update cadence (fortnightly vs every 7 months) and iOS requirement (15.0 vs 17.0). On price, in-app purchases and device support there is nothing between them.

Both are free to download. onTrack sells 1 one-off in-app purchase and Hydra sells 6 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.

onTrack ships an update every 7 months, Hydra fortnightly. The most recent releases landed on October 8, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | onTrack | Hydra |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/ontrack-calorie-tracker/id6745999713/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 7 months | **Fortnightly** |
| Monetization | Free with in-app purchases | — |
| Size | 3 MB | 75 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 17+ | 12+ |
| Developer | [Anuj Shelat](https://appshunter.io/developer/1814751529) | [ANASTASIYA BATURYNA](https://appshunter.io/developer/1869930793) |

## What reviewers say

### onTrack

[App page](https://appshunter.io/ios/app/ontrack-calorie-tracker/id6745999713)

Effortlessly monitor your daily active and resting calorie burn, and track your food intake against personalized targets. Stay motivated with customizable home screen widgets that display your progress at a glance.

**Highlights:** Automatic activity and calorie syncing, Monitor burned calories with progress bars, Track consumed calories and meal targets, Home screen widgets for instant data view, Customizable graph and widget colors

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Customization Feature | $6.99 | one-time |


### Hydra

[App page](https://appshunter.io/ios/app/hydra-water-tracker-and-widget/id6752789853)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VIP Monthly | $5.99 | per month |
| VIP Monthly 3 days free | $5.99 | per month |
| VIP Yearly 85% Off | $10.99 | per year |
| VIP Annual | $29.99 | per year |
| VIP Annual 7 days free | $49.99 | per year |
| VIP Lifetime | $29.99 | one-time |


## Frequently asked questions

### Is onTrack free?

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

### Is Hydra free?

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

### Do onTrack or Hydra have ads?

Hydra shows ads; onTrack does not.

### Which is updated more often, onTrack or Hydra?

onTrack ships an update every 7 months, and Hydra fortnightly. Most recently, onTrack was updated on October 8, 2026 and Hydra 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.*