# EngineCalc vs ESR ProMax

The clearest difference is price: ESR ProMax at Free against EngineCalc's $0.99. ESR ProMax also leads on update cadence (monthly vs every 22 months) and iOS requirement (15.0 vs 26.0). On ads, in-app purchases and device support there is nothing between them.

ESR ProMax is free to download; EngineCalc costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

EngineCalc ships an update every 22 months, ESR ProMax monthly. The most recent releases landed on November 2, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | EngineCalc | ESR ProMax |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | **[3.0 (4 ratings)](https://appshunter.io/ios/app/enginecalc/id378824382/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 57.1% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 22 months | **Monthly** |
| Monetization | Paid | — |
| Size | 13 MB | 65 MB |
| Requires iOS | 26.0 | **15.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [iTrinity, Inc.](https://appshunter.io/developer/547108075) | [Suthipoj tripuwabhrut](https://appshunter.io/developer/1445632800) |

## What reviewers say

### EngineCalc

[App page](https://appshunter.io/ios/app/enginecalc/id378824382)

This utility app provides a collection of essential formulas and calculators for powersports and engine tuning. It allows users to perform complex calculations directly on their iPhone, eliminating the need for a laptop or desktop computer.

**Highlights:** Powersports formulas, Engine tuning calculators, Actual Volume Flow, Air Density, Compression Ratio, Cylinder Displacement, Volumetric Efficiency

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

**In-app purchases:** none


### ESR ProMax

[App page](https://appshunter.io/ios/app/esr-promax/id6772112888)

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

**In-app purchases:** none


## Frequently asked questions

### Is EngineCalc free?

EngineCalc costs $0.99, with no in-app purchases.

### Is ESR ProMax free?

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

### Do EngineCalc or ESR ProMax have ads?

Neither EngineCalc nor ESR ProMax shows ads.

### Which is updated more often, EngineCalc or ESR ProMax?

EngineCalc ships an update every 22 months, and ESR ProMax monthly. Most recently, EngineCalc was updated on November 2, 2026 and ESR ProMax on November 5, 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.*