# BRISTOL vs Probability Sim

The clearest difference is ads: BRISTOL at none against Probability Sim's shown. BRISTOL also leads on update cadence (monthly vs every 10 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. BRISTOL sells 1 one-off in-app purchase and Probability Sim sells 2 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

BRISTOL ships an update monthly, Probability Sim every 10 months. The most recent releases landed on October 25, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | BRISTOL | Probability Sim |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Monthly** | Every 10 months |
| Size | 3 MB | 29 MB |
| Requires iOS | **14.7** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Christopher Britton](https://appshunter.io/developer/1509732288) | [kota tada](https://appshunter.io/developer/1658942612) |

## What reviewers say

### BRISTOL

[App page](https://appshunter.io/ios/app/bristol-calculator/id1509732291)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| bristol calculator storage | $3.99 | one-time |


### Probability Sim

[App page](https://appshunter.io/ios/app/probability-sim-trillion/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 BRISTOL free?

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

### Is Probability Sim free?

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

### Do BRISTOL or Probability Sim have ads?

Probability Sim shows ads; BRISTOL does not.

### Which is updated more often, BRISTOL or Probability Sim?

BRISTOL ships an update monthly, and Probability Sim every 10 months. Most recently, BRISTOL was updated on October 25, 2026 and Probability Sim on October 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.*