# Stair Calculator vs TriangleData

The clearest difference is in-app purchases: TriangleData at none against Stair Calculator's 2. TriangleData also leads on update cadence (every 8 days vs every 3 months) and iOS requirement (12.0 vs 15.0). Stair Calculator's advantage is review sentiment (21% vs 0%). On price, ads and device support there is nothing between them.

Both are free to download. Stair Calculator sells 2 in-app purchases, starting at $9.99 per year. TriangleData asks for nothing beyond the download.

Stair Calculator ships an update every 3 months, TriangleData every 8 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | Stair Calculator | TriangleData |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.1 (740 ratings)](https://appshunter.io/ios/app/stair-calculator-construction/id1493037366/reviews)** | — |
| Number of ratings | **740** | — |
| Positive reviews | **21.4% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 8 days** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 1 MB | 25 MB |
| Requires iOS | 15.0 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Phan Nhat Đang](https://appshunter.io/developer/1437390098) | [Kiryl Sabko](https://appshunter.io/developer/1573151750) |

## What reviewers say

### Stair Calculator

[App page](https://appshunter.io/ios/app/stair-calculator-construction/id1493037366)

This app calculates essential parameters for stair construction, offering flexibility in input and providing multiple step set options. It supports various units and allows results to be easily copied.

**Highlights:** Calculate stair construction parameters, Flexible input for Run or Total Run, Determine largest and smallest step sets, Support for various units, Copy results to clipboard

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Annual Premium Package | $9.99 | per year |
| Unlock all features | $5.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 🚀 Helpful information
- 🚀 Provides useful calculations

**What reviewers complain about**

- 🐛 Doesn't work as expected
- 🔒 No way to cancel subscription
- 🔒 Difficult to cancel trial
- 🤬 Obnoxious ads
- 🤬 Misleading as a learning tool

**Reported bugs**

- Subscription numbers don't add up
- Doesn't provide promised features after purchase

**Requested features**

- Option to uninstall app
- Ability to calculate run based on rise and landing space
- Provide more detailed diagrams and visuals


### TriangleData

[App page](https://appshunter.io/ios/app/triangledata/id1632799728)

This utility app helps you calculate triangle angles and data. It can determine if a corner is 90 degrees by taking measurements and inputting them into the app. You can also use it to calculate right triangle data.

**Highlights:** Calculate triangle angles, Check for 90-degree corners, Input measurements for calculation, Calculate right triangle data

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Stair Calculator free?

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

### Is TriangleData free?

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

### Do Stair Calculator or TriangleData have ads?

Neither Stair Calculator nor TriangleData shows ads.

### Which is updated more often, Stair Calculator or TriangleData?

Stair Calculator ships an update every 3 months, and TriangleData every 8 days. Most recently, Stair Calculator was updated on October 24, 2026 and TriangleData on October 24, 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.*