# Calibration Keeper vs PDF Scanner Document Scanner

The clearest difference is in-app purchases: Calibration Keeper at none against PDF Scanner Document Scanner's 3. Calibration Keeper also leads on ads (none vs shown). PDF Scanner Document Scanner's advantage is update cadence (weekly vs every 16 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. PDF Scanner Document Scanner sells 3 in-app purchases, starting at $4.99 per month. Calibration Keeper asks for nothing beyond the download.

Calibration Keeper ships an update every 16 months, PDF Scanner Document Scanner weekly. The most recent releases landed on September 16, 2026 and September 8, 2026 respectively.

## The numbers

| Metric | Calibration Keeper | PDF Scanner Document Scanner |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 16 months | **Weekly** |
| Size | 22 MB | 57 MB |
| Requires iOS | 15.1 | **14.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Trihydro Corporation](https://appshunter.io/developer/920601995) | [Shraddha Limbasiya](https://appshunter.io/developer/1713525187) |

## What reviewers say

### Calibration Keeper

[App page](https://appshunter.io/ios/app/calibration-keeper/id1465790622)

**Features:** macOS Compatibility

**In-app purchases:** none


### PDF Scanner Document Scanner

[App page](https://appshunter.io/ios/app/pdf-scanner-document-scanner/id1673341666)

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Premium Access | $4.99 | per month |
| Weekly Premium Access | $5.99 | per 7 days |
| Yearly Premium Access | $49.99 | per year |


## Frequently asked questions

### Is Calibration Keeper free?

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

### Is PDF Scanner Document Scanner free?

PDF Scanner Document Scanner is free to download, with in-app purchases available.

### Do Calibration Keeper or PDF Scanner Document Scanner have ads?

PDF Scanner Document Scanner shows ads; Calibration Keeper does not.

### Which is updated more often, Calibration Keeper or PDF Scanner Document Scanner?

Calibration Keeper ships an update every 16 months, and PDF Scanner Document Scanner weekly. Most recently, Calibration Keeper was updated on September 16, 2026 and PDF Scanner Document Scanner on September 8, 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.*