# TDF Calc vs GadCalc

The clearest difference is update cadence: GadCalc at every 18 months against TDF Calc's every 67 months. On price, rating, ratings volume and ads there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for TDF Calc against 5.0 for GadCalc. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

TDF Calc ships an update every 67 months, GadCalc every 18 months. The most recent releases landed on October 14, 2026 and September 29, 2026 respectively.

## The numbers

| Metric | TDF Calc | GadCalc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/tdf-calc/id312749340/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/gadcalc/id1051070769/reviews) |
| Number of ratings | 1 | **2** |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 67 months | **Every 18 months** |
| Monetization | Free | Free |
| Size | 2 MB | 9 MB |
| Requires iOS | 13.2 | **12.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [Eye Physics](https://appshunter.io/developer/312749343) | [University of Wisconsin-Madison Shared Apps](https://appshunter.io/developer/908478605) |

## What reviewers say

### TDF Calc

[App page](https://appshunter.io/ios/app/tdf-calc/id312749340)

This app calculates the biologically effective dose (BED) for radiation therapy fractionation regimens. It allows for comparisons of different treatment schedules and helps determine dose per fraction based on desired treatment duration.

**Highlights:** Linear-quadratic (LQ) method implementation, Biologically effective dose (BED) calculation, External beam radiation therapy (EBRT) fractionation, Low dose rate (LDR) brachytherapy, Permanent implant brachytherapy, Dose per fraction calculation

**Features:** macOS Compatibility

**In-app purchases:** none


### GadCalc

[App page](https://appshunter.io/ios/app/gadcalc/id1051070769)

This medical app assists with calculating MRI contrast agent doses. It provides access to package inserts and lists standard and specific doses for FDA-approved agents. It's a convenient tool for healthcare professionals.

**Highlights:** Calculate MRI contrast agent dose, View contrast agent package inserts, Access online and offline inserts, Look up standard doses, Find University of Wisconsin specific doses

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

**In-app purchases:** none


## Frequently asked questions

### Is TDF Calc free?

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

### Is GadCalc free?

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

### Which has better reviews, TDF Calc or GadCalc?

TDF Calc and GadCalc are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.

### Do TDF Calc or GadCalc have ads?

Neither TDF Calc nor GadCalc shows ads.

### Which is updated more often, TDF Calc or GadCalc?

TDF Calc ships an update every 67 months, and GadCalc every 18 months. Most recently, TDF Calc was updated on October 14, 2026 and GadCalc on September 29, 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.*