# OB ToolBox vs Bias Cure

The clearest difference is iOS requirement: OB ToolBox at 13.0 against Bias Cure's 17.0. On price, rating, ratings volume and update cadence 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 OB ToolBox against 5.0 for Bias Cure. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on September 21, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | OB ToolBox | Bias Cure |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/ob-toolbox/id1565667366/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/bias-cure/id6761279113/reviews) |
| Number of ratings | **2** | 1 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Monetization | Free | Free |
| Size | 56 MB | 2 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 12+ | 17+ |
| Developer | [Frederick Blair](https://appshunter.io/developer/1565667368) | [Todd Doersch](https://appshunter.io/developer/1888590838) |

## What reviewers say

### OB ToolBox

[App page](https://appshunter.io/ios/app/ob-toolbox/id1565667366)

This app offers a quick reference for essential medical values related to fetal growth, amniotic fluid, and Doppler indices. It includes calculators for preterm birth prediction, cesarean risk, and risk of stillbirth or miscarriage.

**Highlights:** Fetal growth reference values, Estimated fetal weight calculator, Amniotic fluid and Doppler indices, Bishop score reference, Preterm birth predictor, Cesarean risk calculator, Stillbirth and miscarriage risk calculators

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

**In-app purchases:** none


### Bias Cure

[App page](https://appshunter.io/ios/app/bias-cure/id6761279113)

This app helps medical professionals and patients understand the true probability of a condition after a test result. It clarifies complex statistical concepts, allowing for transparent communication of results and informed decision-making.

**Highlights:** Transparent sequential probability updating, Individual 2x2 tables for test interpretation, Visual probability trend graph, Printable validation PDF with source citations, Extensive library of conditions and tests, Manual entry of custom diseases and tests, Built-in help pages explaining Bayes' theorem

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is OB ToolBox free?

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

### Is Bias Cure free?

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

### Which has better reviews, OB ToolBox or Bias Cure?

OB ToolBox and Bias Cure are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.

### Do OB ToolBox or Bias Cure have ads?

Neither OB ToolBox nor Bias Cure shows ads.

### Which is updated more often, OB ToolBox or Bias Cure?

OB ToolBox ships an update every 3 weeks, and Bias Cure every 3 weeks. Most recently, OB ToolBox was updated on September 21, 2026 and Bias Cure on October 1, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*