# Doomsday calculator memory vs Day Genius

The clearest difference is in-app purchases: Doomsday calculator memory at none against Day Genius's 1. Doomsday calculator memory also leads on iOS requirement (17.6 vs 26.0). On price, rating, ratings volume and update cadence there is nothing between them.

Both are free to download. Day Genius sells 1 one-off in-app purchase. Doomsday calculator memory asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for Doomsday calculator memory against 5.0 for Day Genius. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Doomsday calculator memory ships an update every 8 days, Day Genius every 2 weeks. The most recent releases landed on October 9, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Doomsday calculator memory | Day Genius |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/doomsday-calculator-memory/id6503307628/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/day-genius/id6801888644/reviews) |
| Number of ratings | 1 | 1 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 8 days** | Every 2 weeks |
| Monetization | **Free** | Free with in-app purchases |
| Size | 4 MB | 6 MB |
| Requires iOS | **17.6** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Joao Vianna](https://appshunter.io/developer/592830914) | [Craig Ricks](https://appshunter.io/developer/6801888646) |

## 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


### Day Genius

[App page](https://appshunter.io/ios/app/day-genius/id6801888644)

Learn to calculate the weekday for any date without a calendar or phone. This app teaches a step-by-step method with interactive drills and games to master the skill. Unlock advanced features with a one-time purchase.

**Highlights:** Step-by-step weekday calculation method, Interactive drills and flashcards, Two engaging practice games, Progress tracking and weak-spot identification, Reference tables for calculations, Support for historical calendar rules

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Method | $3.99 | one-time |


## Frequently asked questions

### Is Doomsday calculator memory free?

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

### Is Day Genius free?

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

### Which has better reviews, Doomsday calculator memory or Day Genius?

Doomsday calculator memory and Day Genius are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.

### Do Doomsday calculator memory or Day Genius have ads?

Neither Doomsday calculator memory nor Day Genius shows ads.

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

Doomsday calculator memory ships an update every 8 days, and Day Genius every 2 weeks. Most recently, Doomsday calculator memory was updated on October 9, 2026 and Day Genius on October 14, 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.*