# Differential Pressure vs Instrument Toolbox

The clearest difference is price: Differential Pressure at Free against Instrument Toolbox's $1.99. Instrument Toolbox's advantage is update cadence (weekly vs every 4 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Differential Pressure is free to download; Instrument Toolbox costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Differential Pressure ships an update every 4 months, Instrument Toolbox weekly. The most recent releases landed on September 17, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | Differential Pressure | Instrument Toolbox |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Weekly** |
| Monetization | — | Paid |
| Size | 4 MB | 8 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Kane Asia Inc.](https://appshunter.io/developer/1542732944) | [立娜 王](https://appshunter.io/developer/1761096632) |

## What reviewers say

### Differential Pressure

[App page](https://appshunter.io/ios/app/differential-pressure/id1099444569)

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

**In-app purchases:** none


### Instrument Toolbox

[App page](https://appshunter.io/ios/app/instrument-toolbox/id6698856248)

A professional calculator designed for industrial control, automation, and instrumentation engineers. It offers quick conversions and calculations for gas concentration, units, steam properties, flange levels, and pipeline flow. Ideal for both field debugging and engineering design.

**Highlights:** PPM to mg/m³ conversion with compensation, Industrial unit conversion (pressure, volume, temp, etc.), Saturated steam pressure and density calculator, Flange level migration calculations, Pipeline flow and velocity calculator, Real-time calculation results

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

**In-app purchases:** none


## Frequently asked questions

### Is Differential Pressure free?

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

### Is Instrument Toolbox free?

Instrument Toolbox costs $1.99, with no in-app purchases.

### Do Differential Pressure or Instrument Toolbox have ads?

Neither Differential Pressure nor Instrument Toolbox shows ads.

### Which is updated more often, Differential Pressure or Instrument Toolbox?

Differential Pressure ships an update every 4 months, and Instrument Toolbox weekly. Most recently, Differential Pressure was updated on September 17, 2026 and Instrument Toolbox on September 23, 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.*