# Z Smart Fit vs BuiltDiff

The clearest difference is iOS requirement: Z Smart Fit at 12.0 against BuiltDiff's 17.0. On price, update cadence, ads and in-app purchases there is nothing between them.

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

Z Smart Fit ships an update every 11 days, BuiltDiff every 2 weeks. Both last shipped on October 4, 2026.

## The numbers

| Metric | Z Smart Fit | BuiltDiff |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/builtdiff/id6478643263/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 11 days** | Every 2 weeks |
| Monetization | — | Free |
| Size | 82 MB | 3 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | iPhone, iPod | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [Shenzhen Zhongxinlong Semiconductor Co., Ltd.](https://appshunter.io/developer/1675185952) | [Timmy Nguyen](https://appshunter.io/developer/1679678398) |

## What reviewers say

### Z Smart Fit

[App page](https://appshunter.io/ios/app/z-smart-fit/id6446196326)

**Features:** macOS Compatibility

**In-app purchases:** none


### BuiltDiff

[App page](https://appshunter.io/ios/app/builtdiff/id6478643263)

Log your weightlifting sets and reps with a clean, distraction-free interface. Visualize your progress with charts and personalize the app's appearance. Enjoy offline functionality and a sign-up-free experience for efficient workouts.

**Highlights:** Log lifts, sets, and reps, Create custom workout routines, Offline functionality, Sign-up-free experience, Visualize progress with charts, Personalize app appearance

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Z Smart Fit free?

Z Smart Fit is free to download, with no in-app purchases.

### Is BuiltDiff free?

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

### Do Z Smart Fit or BuiltDiff have ads?

Neither Z Smart Fit nor BuiltDiff shows ads.

### Which is updated more often, Z Smart Fit or BuiltDiff?

Z Smart Fit ships an update every 11 days, and BuiltDiff every 2 weeks. Most recently, Z Smart Fit was updated on October 4, 2026 and BuiltDiff on October 4, 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.*