# Stoichiometry Pro vs DrPhos' Stoichiometry

The clearest difference is in-app purchases: Stoichiometry Pro at none against DrPhos' Stoichiometry's 11. DrPhos' Stoichiometry's advantage is update cadence (every 3 weeks vs every 4 months) and price ($0.99 vs $3.99). On ads, device support and iOS requirement there is nothing between them.

Stoichiometry Pro costs $3.99 and DrPhos' Stoichiometry $0.99 up front. DrPhos' Stoichiometry sells 11 one-off in-app purchases. Stoichiometry Pro asks for nothing beyond the download.

Stoichiometry Pro ships an update every 4 months, DrPhos' Stoichiometry every 3 weeks. The most recent releases landed on August 20, 2026 and September 20, 2026 respectively.

## The numbers

| Metric | Stoichiometry Pro | DrPhos' Stoichiometry |
| --- | --- | --- |
| Price | $3.99 | **$0.99** |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/drphos-stoichiometry/id6475633178/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 weeks** |
| Monetization | — | Paid |
| Size | 2 MB | 15 MB |
| Requires iOS | **17.0** | 17.2 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Roman Volinsky](https://appshunter.io/developer/977951850) | [Monte L Helm](https://appshunter.io/developer/1715082616) |

## What reviewers say

### Stoichiometry Pro

[App page](https://appshunter.io/ios/app/stoichiometry-pro/id1546919546)

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

**In-app purchases:** none


### DrPhos' Stoichiometry

[App page](https://appshunter.io/ios/app/drphos-stoichiometry/id6475633178)

This tool simplifies solving chemical reaction problems by allowing users to input balanced equations and identify known and unknown compounds. It instantly calculates moles and mass, assisting students with various stoichiometry challenges.

**Highlights:** Mole, mass, and volume conversions, Balanced chemical equation support, Compound selection, Limiting reactant detection, High school and college chemistry focus

**Features:** macOS Compatibility

**In-app purchases (11)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Significant Figures Counter | $0.99 | one-time |
| Science Calculator | $0.99 | one-time |
| Quadratic Equation Solver | $0.99 | one-time |
| Kinetics | $0.99 | one-time |
| Molar Mass Calculator | $0.99 | one-time |
| General Chemistry Naming | $0.99 | one-time |
| Ionic Compound Builder | $0.99 | one-time |
| Solution Concentrations | $0.99 | one-time |
| Reaction Balancer | $0.99 | one-time |
| pH Calculator | $0.99 | one-time |
| Stoichiometry | $0.99 | one-time |


## Frequently asked questions

### Is Stoichiometry Pro free?

Stoichiometry Pro costs $3.99, with no in-app purchases.

### Is DrPhos' Stoichiometry free?

DrPhos' Stoichiometry costs $0.99, and also offers in-app purchases.

### Do Stoichiometry Pro or DrPhos' Stoichiometry have ads?

Neither Stoichiometry Pro nor DrPhos' Stoichiometry shows ads.

### Which is updated more often, Stoichiometry Pro or DrPhos' Stoichiometry?

Stoichiometry Pro ships an update every 4 months, and DrPhos' Stoichiometry every 3 weeks. Most recently, Stoichiometry Pro was updated on August 20, 2026 and DrPhos' Stoichiometry on September 20, 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.*