# Calc pH vs Air Density Calculator

The clearest difference is price: Calc pH at Free against Air Density Calculator's $2.99. Calc pH also leads on iOS requirement (9.0 vs 17.6). Air Density Calculator's advantage is update cadence (every 20 months vs every 59 months). On ads, in-app purchases and device support there is nothing between them.

Calc pH is free to download; Air Density Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Calc pH ships an update every 59 months, Air Density Calculator every 20 months. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Calc pH | Air Density Calculator |
| --- | --- | --- |
| Price | **Free** | $2.99 |
| Rating | — | **[3.8 (4 ratings)](https://appshunter.io/ios/app/air-density-calculator/id1421668162/reviews)** |
| Number of ratings | — | **4** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 59 months | **Every 20 months** |
| Monetization | — | Paid |
| Size | 0 MB | 1 MB |
| Requires iOS | **9.0** | 17.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ZOFTERM](https://appshunter.io/developer/557950548) | [Nitrio](https://appshunter.io/developer/321121189) |

## What reviewers say

### Calc pH

[App page](https://appshunter.io/ios/app/calc-ph/id566354963)

**Features:** macOS Compatibility

**In-app purchases:** none


### Air Density Calculator

[App page](https://appshunter.io/ios/app/air-density-calculator/id1421668162)

Instantly calculate air density and atmospheric properties with this offline engineering tool. Features three modes for density, reverse solving, and altitude estimation, with flexible unit support and calculation breakdown.

**Highlights:** Accurate air density calculation, Density, Reverse Solve, and Altitude modes, Flexible unit support, Show calculation steps, Tap to copy results, Calculation history, Offline functionality

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

**In-app purchases:** none


## Frequently asked questions

### Is Calc pH free?

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

### Is Air Density Calculator free?

Air Density Calculator costs $2.99, with no in-app purchases.

### Do Calc pH or Air Density Calculator have ads?

Neither Calc pH nor Air Density Calculator shows ads.

### Which is updated more often, Calc pH or Air Density Calculator?

Calc pH ships an update every 59 months, and Air Density Calculator every 20 months. Most recently, Calc pH was updated on November 1, 2026 and Air Density Calculator on November 2, 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.*