Comparison

True Proof vs Haverly's PetroCalc

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

True Proof

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
Read full description

True Proof calculates the true proof of a water-alcohol mixture at a reference temperature, using the measured apparent proof from a hydrometer reading and the temperature at the time of the reading. True Proof also performs gauging calculations, and can calculate dilutions taking full account of the temperature-dependent nonideal mixing of water and alcohol. Calculations are logged, and may be annotated and emailed for archiving. Multiple units support large-scale distillers and hobby-scale distillers alike, in the US and abroad: concentration measurement in proof, ABV, or density ; temperature in °F or °C; abundance in US gallon, liter, pound, kg, US ton, or metric tonne, etc. The reference temperature can be selected for US (60ºF) or international (20ºC), or any other value in the range [-20ºC,40ºC]. The instrument thermal expansivity can be selected, which enables application to vibrating tube densitometers in addition to hydrometers. Two separate computational models are employed - one based on the (US) TTB gauging manual, and one based on OIML (UK, EU, Canada, etc) data. The computer model is limited in temperature and proof range to that spanned by government standard tables.

About

Haverly's PetroCalc

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
Read full description

PETROCALC – THE TRUSTED PETROLEUM CALCULATOR IN YOUR POCKET PetroCalc is the all‑in‑one oil & gas calculator that engineers, technicians, and students rely on for fast, accurate viscosity calculations, crude‑oil blending, and every other petroleum‑property task. Whether you need an oil calculator for the field, a crude‑oil calculator for the lab, or a classroom reference, PetroCalc streamlines every petroleum calculation—from viscosity blending to heating‑value look‑ups—completely offline. KEY FEATURES • Unit Conversion – Instantly switch between energy units (MJ/m³, MBTU/bbl, BTU/gal, kCal), temperature (°F/°C), pressure (psi/bar), oil‑density & gravity (kg/m³, API °, specific gravity), kinematic ↔ dynamic viscosity (cSt ↔ cP) and operational scales (SUS, SFS, Redwood I, Engler °), plus calorific‑value conversions and more with our intuitive oil & gas calculator interface. • Distillation‑Curve Tools – Convert temperatures between TBP, ASTM D86, D1160, and D2887 scales and perform yield‑temperature interpolation for full distillation‑curve analysis. • Blending Tools – Execute precise crude‑oil blending and petroleum blending for RVP, Flash Point, Smoke Point, Pour / Cloud / Freeze Point, API Gravity, Aniline Point, Mercaptan Sulfur, Nitrogen, and custom fractions. • Fuel Property Indices – Compute Cetane Index (ASTM D4737 A/B, D976), Driveability Index, Refractive Index, and additional viscosity calculations. • Heating Values – Obtain Gross & Net HHV in MJ/m³, MBTU/bbl, BTU/gal, kCal/kg, and more. • Boiling‑Point Utilities – IBP/EBP plus five average‑boiling‑point methods (Volume, Weight, Molal, Cubic, Mean). • K‑Factor Calculations – UOP K, Watson K, VRC K, Whole‑Crude K at any temperature. • Viscosity Prediction – Single‑point, two‑point (Twu), and API 11A4.2 models with built‑in viscosity‑blending conversions. WHY PETROCALC? • Developed by Haverly Systems, a leader in petroleum‑process modeling. • Optimized for petroleum, chemical, and process engineers—and perfect for students in engineering courses who need a dependable petroleum calculator and oil calculator for coursework. • Works fully offline—no data connection required on‑site. • Simple, accurate, and fast: the only crude‑oil calculator and petroleum‑blending tool you’ll ever need. Download PetroCalc today and tackle every oil & gas calculation—from distillation‑curve conversions and viscosity blending to heating values—with confidence.

Screenshots

True Proof4 screens
Haverly's PetroCalc4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard3 real differences · 7 level
True Proof versus Haverly's PetroCalc: the parameters behind the verdict, then further details
ParameterTrue ProofHaverly's PetroCalc
Price$9.99Free — better
Rating4.0 (4 ratings)4.7 (3 ratings) — better
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings4 — better3
Update frequencyEvery 4 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS12.0 — better12.2
Further details — not scored
Size8 MB54 MB
Age rating17+4+
DeveloperGreg MillerHaverly Systems, Inc.

Customer experience

True Proof

All ratings4 ratings
Positive75.0%
Neutral0.0%
Negative25.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Haverly's PetroCalc

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

True Proof

No in-app purchases

None

Haverly's PetroCalc

No in-app purchases

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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