# UltraMemory Spaced Repetition vs Unfog

The clearest difference is device support: UltraMemory Spaced Repetition at 3 against Unfog's 1. UltraMemory Spaced Repetition also leads on iOS requirement (15.1 vs 17.0). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. UltraMemory Spaced Repetition sells 2 in-app purchases, starting at $12.99 per month and Unfog sells 3 in-app purchases, starting at $2.99 per 7 days. Whichever you choose, the download price is not the number that matters.

UltraMemory Spaced Repetition ships an update every 4 days, Unfog every 2 days. The most recent releases landed on October 28, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | UltraMemory Spaced Repetition | Unfog |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 4 days | **Every 2 days** |
| Size | 65 MB | 80 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Joel Lovera](https://appshunter.io/developer/1674403024) | [BITSEC SP. Z O.O.](https://appshunter.io/developer/1801990616) |

## What reviewers say

### UltraMemory Spaced Repetition

[App page](https://appshunter.io/ios/app/ultramemory-spaced-repetition/id6757965833)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $12.99 | per month |
| Pro | $99.99 | per year |


### Unfog

[App page](https://appshunter.io/ios/app/unfog-feynman-study-notes/id6776245365)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unfog weekly | $2.99 | per 7 days |
| Unfog Monthly | $17.99 | per month |
| Unfog Annual | $29.99 | per year |


## Frequently asked questions

### Is UltraMemory Spaced Repetition free?

UltraMemory Spaced Repetition is free to download, with in-app purchases available.

### Is Unfog free?

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

### Do UltraMemory Spaced Repetition or Unfog have ads?

Neither UltraMemory Spaced Repetition nor Unfog shows ads.

### Which is updated more often, UltraMemory Spaced Repetition or Unfog?

UltraMemory Spaced Repetition ships an update every 4 days, and Unfog every 2 days. Most recently, UltraMemory Spaced Repetition was updated on October 28, 2026 and Unfog on October 25, 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.*