# Impossible Alarm vs OnLock

The clearest difference is in-app purchases: OnLock at none against Impossible Alarm's 2. OnLock also leads on ads (none vs shown). Impossible Alarm's advantage is update cadence (every 4 days vs every 5 weeks). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Impossible Alarm sells 2 in-app purchases, starting at $3.99 per month. OnLock asks for nothing beyond the download.

Impossible Alarm ships an update every 4 days, OnLock every 5 weeks. The most recent releases landed on October 31, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | Impossible Alarm | OnLock |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (3 ratings)](https://appshunter.io/ios/app/onlock-study-timer/id6770142774/reviews)** |
| Number of ratings | — | **3** |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 4 days** | Every 5 weeks |
| Monetization | — | Free |
| Size | 101 MB | 48 MB |
| Requires iOS | 17.0 | **16.0** |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Tarik Bilen](https://appshunter.io/developer/1888521003) | [Ting Ting Xu](https://appshunter.io/developer/1896719164) |

## What reviewers say

### Impossible Alarm

[App page](https://appshunter.io/ios/app/impossible-alarm-wake-up/id6761268513)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Impossible Alarm Pro | $3.99 | per month |
| Impossible Alarm Pro Yearly | $24.99 | per year |


### OnLock

[App page](https://appshunter.io/ios/app/onlock-study-timer/id6770142774)

This app enforces focus by locking distracting applications at the operating system level. It uses AI to verify study sessions with photos, ensuring your progress is genuine and building an earned streak. Features include scheduled blocks, intent journaling, and focus intelligence insights.

**Highlights:** OS-level distraction blocking, AI-verified study sessions, Streak building, Scheduled recurring blocks, Intent journaling, Focus intelligence insights, Home screen widgets

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

**In-app purchases:** none


## Frequently asked questions

### Is Impossible Alarm free?

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

### Is OnLock free?

OnLock is free to download, with no in-app purchases.

### Do Impossible Alarm or OnLock have ads?

Impossible Alarm shows ads; OnLock does not.

### Which is updated more often, Impossible Alarm or OnLock?

Impossible Alarm ships an update every 4 days, and OnLock every 5 weeks. Most recently, Impossible Alarm was updated on October 31, 2026 and OnLock on November 5, 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.*