# ISO Fits vs GD&T

The clearest difference is in-app purchases: GD&T at none against ISO Fits's 1. ISO Fits's advantage is update cadence (every 5 months vs every 11 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. ISO Fits sells 1 one-off in-app purchase. GD&T asks for nothing beyond the download.

ISO Fits ships an update every 5 months, GD&T every 11 months. The most recent releases landed on November 6, 2026 and October 26, 2026 respectively.

## The numbers

| Metric | ISO Fits | GD&T |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (6 ratings)](https://appshunter.io/ios/app/iso-fits/id396863755/reviews)** | — |
| Number of ratings | **6** | — |
| Positive reviews | 94.6% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 5 months** | Every 11 months |
| Monetization | Free with in-app purchases | — |
| Size | 66 MB | 56 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Trelleborg Sealing Solutions](https://appshunter.io/developer/396863758) | [Carl Zeiss AG](https://appshunter.io/developer/488066215) |

## What reviewers say

### ISO Fits

[App page](https://appshunter.io/ios/app/iso-fits/id396863755)

Calculate ISO fits and tolerances for shafts and bores. Supports metric and inch units, displays detailed fit definitions, and includes visual charts and educational videos.

**Highlights:** ISO fits calculation, Tolerance class display, Metric/inch unit switching, Tolerance charts, Updated YouTube videos

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version with complete ISO286 Standard | $1.99 | one-time |


### GD&T

[App page](https://appshunter.io/ios/app/gd-and-t/id627973440)

**In-app purchases:** none


## Frequently asked questions

### Is ISO Fits free?

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

### Is GD&T free?

GD&T is free to download, with no in-app purchases.

### Do ISO Fits or GD&T have ads?

Neither ISO Fits nor GD&T shows ads.

### Which is updated more often, ISO Fits or GD&T?

ISO Fits ships an update every 5 months, and GD&T every 11 months. Most recently, ISO Fits was updated on November 6, 2026 and GD&T on October 26, 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.*