# DrPhos' pH Calculator vs Flashcards by SwiftStudy

The clearest difference is price: Flashcards by SwiftStudy at Free against DrPhos' pH Calculator's $0.99. Flashcards by SwiftStudy also leads on rating (4.6 vs 3.7) and update cadence (every 2 days vs every 10 days). On ads, in-app purchases, monetization model and device support there is nothing between them.

Flashcards by SwiftStudy is free to download; DrPhos' pH Calculator costs $0.99 up front. DrPhos' pH Calculator sells 11 one-off in-app purchases and Flashcards by SwiftStudy sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Flashcards by SwiftStudy holds the better App Store score, 4.6 against 3.7. That said, the two scores are not equally well evidenced: Flashcards by SwiftStudy has 31 ratings behind it against 3, so its average is the more settled of the two.

DrPhos' pH Calculator ships an update every 10 days, Flashcards by SwiftStudy every 2 days. The most recent releases landed on June 4, 2026 and June 1, 2026 respectively.

## The numbers

| Metric | DrPhos' pH Calculator | Flashcards by SwiftStudy |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | [3.7 (3 ratings)](https://appshunter.io/ios/app/drphos-ph-calculator/id6477762321/reviews) | **[4.6 (31 ratings)](https://appshunter.io/ios/app/flashcards-by-swiftstudy/id6502048405/reviews)** |
| Number of ratings | 3 | **31** |
| Positive reviews | — | 84.6% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 10 days | **Every 2 days** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 15 MB | 16 MB |
| Requires iOS | 17.2 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Monte L Helm](https://appshunter.io/developer/1715082616) | [KD incubator UG (haftungsbeschrankt)](https://appshunter.io/developer/1744327425) |

## What reviewers say

### DrPhos' pH Calculator

[App page](https://appshunter.io/ios/app/drphos-ph-calculator/id6477762321)

This tool instantly calculates pH, pOH, and ion concentrations for strong and weak acids and bases. It supports molarity and scientific notation, ensuring accurate results for general chemistry problems.

**Highlights:** Calculate pH, pOH, [H⁺], or [OH⁻], Handles strong and weak acids/bases, Supports Ka and Kb values, Built-in molarity and scientific notation, Automatic pH + pOH = 14, Clean, focused layout

**Features:** macOS Compatibility

**In-app purchases (11)**

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


### Flashcards by SwiftStudy

[App page](https://appshunter.io/ios/app/flashcards-by-swiftstudy/id6502048405)

Create and study double-sided flashcards with text and visuals. Organize them into custom stacks and track your progress through four mastery levels. Study from anywhere on any device and build a consistent learning streak.

**Highlights:** Double-sided flashcards with text and visuals, Organize cards into topic-based stacks, Customizable stack designs, Four mastery levels: New, In practice, Familiar, Mastered, Cross-device study access, Learning streak tracking

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Flashcards - Coffee tip | $3.99 | one-time |
| Drink Tip | $9.99 | one-time |
| Lunch Tip | $19.99 | one-time |


## Frequently asked questions

### Is DrPhos' pH Calculator free?

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

### Is Flashcards by SwiftStudy free?

Flashcards by SwiftStudy is free to download, with in-app purchases available.

### Which has better reviews, DrPhos' pH Calculator or Flashcards by SwiftStudy?

Flashcards by SwiftStudy is rated higher. DrPhos' pH Calculator averages 3.7 out of 5 from 3 ratings, while Flashcards by SwiftStudy averages 4.6 from 31 ratings.

### Do DrPhos' pH Calculator or Flashcards by SwiftStudy have ads?

Neither DrPhos' pH Calculator nor Flashcards by SwiftStudy shows ads.

### Which is updated more often, DrPhos' pH Calculator or Flashcards by SwiftStudy?

DrPhos' pH Calculator ships an update every 10 days, and Flashcards by SwiftStudy every 2 days. Most recently, DrPhos' pH Calculator was updated on June 4, 2026 and Flashcards by SwiftStudy on June 1, 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.*