# Modulo Calculator. vs Doomsday Trainer

The clearest difference is ads: Doomsday Trainer at none against Modulo Calculator.'s shown. Doomsday Trainer also leads on update cadence (every 5 days vs every 4 months). Modulo Calculator.'s advantage is iOS requirement (12.0 vs 15.0). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Modulo Calculator. ships an update every 4 months, Doomsday Trainer every 5 days. The most recent releases landed on October 9, 2026 and September 30, 2026 respectively.

## The numbers

| Metric | Modulo Calculator. | Doomsday Trainer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (2 ratings)](https://appshunter.io/ios/app/doomsday-trainer/id6760719687/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 4 months | **Every 5 days** |
| Monetization | — | Free |
| Size | 29 MB | 15 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Milos Lukas Ziolkowski](https://appshunter.io/developer/1778486821) | [Maarten Claessen](https://appshunter.io/developer/1885901059) |

## What reviewers say

### Modulo Calculator.

[App page](https://appshunter.io/ios/app/modulo-calculator/id6737914141)

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

**In-app purchases:** none


### Doomsday Trainer

[App page](https://appshunter.io/ios/app/doomsday-trainer/id6760719687)

Master the Doomsday Algorithm to instantly calculate the day of the week for any historical date. Engage in timed challenges, compete against others, and practice various calculation methods to improve your speed and accuracy.

**Highlights:** Doomsday Algorithm calculation, Timed streak challenges, 1-on-1 live battles, Multiple training methods, Targeted component drills, Step-by-step tutorial

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

**In-app purchases:** none


## Frequently asked questions

### Is Modulo Calculator. free?

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

### Is Doomsday Trainer free?

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

### Do Modulo Calculator. or Doomsday Trainer have ads?

Modulo Calculator. shows ads; Doomsday Trainer does not.

### Which is updated more often, Modulo Calculator. or Doomsday Trainer?

Modulo Calculator. ships an update every 4 months, and Doomsday Trainer every 5 days. Most recently, Modulo Calculator. was updated on October 9, 2026 and Doomsday Trainer on September 30, 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.*