# Blackboard vs Calibration Meter

The clearest difference is ads: Calibration Meter at none against Blackboard's shown. Blackboard's advantage is device support (3 vs 1) and iOS requirement (15.6 vs 17.0). On price 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.

## The numbers

| Metric | Blackboard | Calibration Meter |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (14 ratings)](https://appshunter.io/ios/app/blackboard-simple/id1600026235/reviews)** | — |
| Number of ratings | **14** | — |
| Positive reviews | 16.7% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | — |
| Monetization | Ad-supported | — |
| Size | 13 MB | 1 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Ryouhei Azuma](https://appshunter.io/developer/1353297781) | [小江 王](https://appshunter.io/developer/6817158658) |

## What reviewers say

### Blackboard

[App page](https://appshunter.io/ios/app/blackboard-simple/id1600026235)

This drawing app mimics a physical blackboard, allowing users to sketch and write with white and red pens. It supports multi-touch for collaborative drawing and enables saving creations as images. Use it as a digital notepad or for artistic expression.

**Highlights:** Blackboard simulation, White and red pen tools, Multi-touch drawing, Save drawings as images, Digital notepad functionality

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

**In-app purchases:** none


### Calibration Meter

[App page](https://appshunter.io/ios/app/calibration-meter/id6817168753)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Blackboard free?

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

### Is Calibration Meter free?

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

### Do Blackboard or Calibration Meter have ads?

Blackboard shows ads; Calibration Meter does not.

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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.*