# QTc vs StudyCoorCalc

The clearest difference is in-app purchases: QTc at none against StudyCoorCalc's 2. StudyCoorCalc's advantage is update cadence (every 4 days vs every 4 months) and iOS requirement (17.0 vs 27.0). On price, ads and device support there is nothing between them.

Both are free to download. StudyCoorCalc sells 2 in-app purchases, starting at $2.99 per month. QTc asks for nothing beyond the download.

QTc ships an update every 4 months, StudyCoorCalc every 4 days. The most recent releases landed on November 2, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | QTc | StudyCoorCalc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (51 ratings)](https://appshunter.io/ios/app/qtc-calculator/id1354439139/reviews)** | — |
| Number of ratings | **51** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 4 days** |
| Monetization | Free | — |
| Size | 1 MB | 4 MB |
| Requires iOS | 27.0 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 17+ | 17+ |
| Developer | [Marian Stiehler](https://appshunter.io/developer/1354439138) | [Brent Bloomquist](https://appshunter.io/developer/1840528747) |

## What reviewers say

### QTc

[App page](https://appshunter.io/ios/app/qtc-calculator/id1354439139)

This medical app calculates QTc using nine different formulas. It allows users to input heart rate or RR interval and QT interval length for quick results. An Apple Watch app is also included for convenient access.

**Highlights:** Nine QTc calculation formulas, Input heart rate or RR interval, Input QT interval length, Apple Watch app integration, No personal data collection, Offline functionality

**In-app purchases:** none


### StudyCoorCalc

[App page](https://appshunter.io/ios/app/studycoorcalc/id6752674254)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $2.99 | per month |
| Pro Yearly | $19.99 | per year |


## Frequently asked questions

### Is QTc free?

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

### Is StudyCoorCalc free?

StudyCoorCalc is free to download, with in-app purchases available.

### Do QTc or StudyCoorCalc have ads?

Neither QTc nor StudyCoorCalc shows ads.

### Which is updated more often, QTc or StudyCoorCalc?

QTc ships an update every 4 months, and StudyCoorCalc every 4 days. Most recently, QTc was updated on November 2, 2026 and StudyCoorCalc on October 30, 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.*