# Doomsday calculator memory vs Aritmo

The clearest difference is in-app purchases: Doomsday calculator memory at none against Aritmo's 2. Doomsday calculator memory also leads on ads (none vs shown). Aritmo's advantage is update cadence (every 2 days vs every 8 days). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Aritmo sells 2 in-app purchases, starting at $3.99 per month. Doomsday calculator memory asks for nothing beyond the download.

Doomsday calculator memory ships an update every 8 days, Aritmo every 2 days. The most recent releases landed on October 9, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Doomsday calculator memory | Aritmo |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/doomsday-calculator-memory/id6503307628/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 8 days | **Every 2 days** |
| Monetization | Free | — |
| Size | 4 MB | 13 MB |
| Requires iOS | 17.6 | **16.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Joao Vianna](https://appshunter.io/developer/592830914) | [LUCCA EMMANUEL PINELI SIMOES LTDA](https://appshunter.io/developer/1884998353) |

## What reviewers say

### Doomsday calculator memory

[App page](https://appshunter.io/ios/app/doomsday-calculator-memory/id6503307628)

Practice and memorize a method for quickly calculating the weekday of any given date. This app is based on John Conway's 1970 mathematical system, allowing you to test your abilities without external tools.

**Highlights:** Practice date calculations, Memorize weekday method, Based on John Conway's system, No external tools needed, Test your abilities

**Features:** macOS Compatibility

**In-app purchases:** none


### Aritmo

[App page](https://appshunter.io/ios/app/aritmo/id6760564207)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Aritmo Premium | $3.99 | per month |
| Aritmo Yearly Premium Access | $29.99 | per year |


## Frequently asked questions

### Is Doomsday calculator memory free?

Doomsday calculator memory is free to download, with no in-app purchases.

### Is Aritmo free?

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

### Do Doomsday calculator memory or Aritmo have ads?

Aritmo shows ads; Doomsday calculator memory does not.

### Which is updated more often, Doomsday calculator memory or Aritmo?

Doomsday calculator memory ships an update every 8 days, and Aritmo every 2 days. Most recently, Doomsday calculator memory was updated on October 9, 2026 and Aritmo on October 31, 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.*