# True Proof vs Haverly's PetroCalc

The clearest difference is price: Haverly's PetroCalc at Free against True Proof's $9.99. Haverly's PetroCalc also leads on rating (4.7 vs 4.0). On review sentiment, ratings volume, update cadence and ads there is nothing between them.

Haverly's PetroCalc is free to download; True Proof costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Haverly's PetroCalc holds the better App Store score, 4.7 against 4.0. Both are backed by a comparable volume of ratings — 4 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

True Proof ships an update every 4 months, Haverly's PetroCalc every 2 months. The most recent releases landed on September 12, 2026 and September 8, 2026 respectively.

## The numbers

| Metric | True Proof | Haverly's PetroCalc |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | [4.0 (4 ratings)](https://appshunter.io/ios/app/true-proof/id901015790/reviews) | **[4.7 (3 ratings)](https://appshunter.io/ios/app/haverlys-petrocalc/id1125079839/reviews)** |
| Number of ratings | **4** | 3 |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Paid | **Free** |
| Size | 8 MB | 54 MB |
| Requires iOS | **12.0** | 12.2 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 17+ | 4+ |
| Developer | [Greg Miller](https://appshunter.io/developer/901015793) | [Haverly Systems, Inc.](https://appshunter.io/developer/1125079838) |

## What reviewers say

### True Proof

[App page](https://appshunter.io/ios/app/true-proof/id901015790)

This app calculates the true proof of water-alcohol mixtures based on hydrometer readings and temperature. It also performs gauging calculations and dilutions, accounting for temperature-dependent mixing. Results can be logged, annotated, and emailed for record-keeping.

**Highlights:** True proof calculation, Gauging calculations, Dilution calculations, Temperature compensation, Log and email results, Multiple unit support

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

**In-app purchases:** none


### Haverly's PetroCalc

[App page](https://appshunter.io/ios/app/haverlys-petrocalc/id1125079839)

This application provides engineers, technicians, and students with a comprehensive set of tools for petroleum property calculations. It offers features for unit conversion, crude oil blending, viscosity prediction, and distillation curve analysis, all accessible offline.

**Highlights:** Unit conversion for energy, temperature, pressure, and viscosity, Distillation curve analysis and interpolation, Crude oil and petroleum blending calculations, Fuel property index computation, Heating value calculations, Boiling point utilities, K-factor calculations, Viscosity prediction models

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is True Proof free?

True Proof costs $9.99, with no in-app purchases.

### Is Haverly's PetroCalc free?

Haverly's PetroCalc is free to download, with no in-app purchases.

### Which has better reviews, True Proof or Haverly's PetroCalc?

Haverly's PetroCalc is rated higher. True Proof averages 4.0 out of 5 from 4 ratings, while Haverly's PetroCalc averages 4.7 from 3 ratings.

### Do True Proof or Haverly's PetroCalc have ads?

Neither True Proof nor Haverly's PetroCalc shows ads.

### Which is updated more often, True Proof or Haverly's PetroCalc?

True Proof ships an update every 4 months, and Haverly's PetroCalc every 2 months. Most recently, True Proof was updated on September 12, 2026 and Haverly's PetroCalc on September 8, 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.*