# Probability vs Trillion

The clearest difference is in-app purchases: Probability at none against Trillion's 2. Probability also leads on ads (none vs shown) and iOS requirement (9.0 vs 13.0). On price, update cadence and device support there is nothing between them.

Both are free to download. Trillion sells 2 in-app purchases, starting at $4.99 per month. Probability asks for nothing beyond the download.

Probability ships an update every 18 months, Trillion every 12 months. The most recent releases landed on October 6, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Probability | Trillion |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 18 months | **Every 12 months** |
| Size | 1 MB | 29 MB |
| Requires iOS | **9.0** | 13.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [domesticusdevelop](https://appshunter.io/developer/373834594) | [kota tada](https://appshunter.io/developer/1658942612) |

## What reviewers say

### Probability

[App page](https://appshunter.io/ios/app/probability-dd/id1451460705)

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

**In-app purchases:** none


### Trillion

[App page](https://appshunter.io/ios/app/trillion-probability-simu/id6743378063)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Ad-free for 1 month | $4.99 | per month |
| Ad-free for 1 year | $49.99 | per year |


## Frequently asked questions

### Is Probability free?

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

### Is Trillion free?

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

### Do Probability or Trillion have ads?

Trillion shows ads; Probability does not.

### Which is updated more often, Probability or Trillion?

Probability ships an update every 18 months, and Trillion every 12 months. Most recently, Probability was updated on October 6, 2026 and Trillion on October 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.*