EngineCalc vs Rollout Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
EngineCalc
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.
- Powersports formulas
- Engine tuning calculators
- Actual Volume Flow
- Air Density
- Compression Ratio
- Cylinder Displacement
- Volumetric Efficiency
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EngineCalc is the essential toolkit for engine builders, mechanics, and motorsport enthusiasts. Whether you're building a street rod, a race engine, or modifying a performance vehicle, EngineCalc puts the math at your fingertips — with the formula shown for every calculation so you always understand exactly what's happening under the hood. CALCULATORS Piston • Piston Speed — mean piston velocity from RPM and stroke • Compression Ratio — from cylinder and chamber volumes • Rod Ratio — connecting rod length to stroke relationship • Rod Length — from block length, stroke, and deck clearance • Piston Dome Volume — dome cc needed to hit a target compression ratio • Compression Height — wristpin height from deck clearance and stroke • Cylinder Displacement — total displacement from bore, stroke, and cylinder count Power • Simple Horsepower — quick HP from RPM and torque • Torque — from horsepower and RPM • Horsepower — using MEP, displacement, compression ratio, and VE • Corrected BHP — sea-level horsepower adjusted for altitude • BHP Loss — how much power elevation costs you • Volumetric Efficiency — actual vs. theoretical airflow • Theoretical Volume Flow — maximum CFM at a given RPM • Actual Volume Flow — real-world CFM with volumetric efficiency Fuel • Air Density — available oxygen from altitude and temperature • Mass Flow — air mass moving through the engine per minute • BSFC — brake specific fuel consumption and engine efficiency UNIT CONVERSIONS Thirteen categories covering every unit an engine builder needs: Torque • Pressure • Power • Volume • Temperature • Length • Mass Speed • Force • Fuel Efficiency • Frequency • Energy • Angle Type a value in any unit and all others update instantly. Categories you use most rise to the top automatically. FEATURES • Search — jump straight to any calculator by name • Metric and Standard measurement systems — switch anytime, values convert automatically • Formulas displayed for every calculator — no black boxes • Results shown with units, and shareable to any app or message • Result history — your last stored values for each calculator • Built-in guide — contextual help for calculators and conversions, available anytime • Works completely offline — no account, no subscription, no data collected
Rollout Calculator
This utility app calculates the travel distance of an RC direct drive car per motor rotation. It simplifies setup by displaying results in three easy-to-read tables, allowing users to select gear teeth and tire diameter.
- Rollout distance calculation
- Three display tables
- Pinion and spur gear selection
- Tire diameter input
- Pitch setting
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“Rollout" means the travel distance (mm) of a RC direct drive car with one rotation of the motor. It is said that Rollout is one of the important items on the setup. "Rollout Calculator - RC DD car" calculates Rollout with a simple operation and displays it in three tables that are easy to use for setup. (How to use) - Select from three types with two tables to display on the screen from the "Display types" button. - Tap the button on the top of the screen to open the picker, so select the number of pinion gear teeth, spur gear teeth, and tire diameter to be the center of the table. - Select the pitch of the selection item from the "Setting" button. The developer assumes no responsibility for any accident, violation, loss or claims by third parties which may arise from the use of this app.
Screenshots
Verdict
The clearest difference is price: Rollout Calculator at Free against EngineCalc's $0.99. Rollout Calculator also leads on rating (4.9 vs 3.0) and update cadence (every 2 months vs every 22 months). EngineCalc's advantage is ads (none vs shown). On ratings volume and in-app purchases 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
Rollout Calculator is free to download; EngineCalc costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Rollout Calculator holds the better App Store score, 4.9 against 3.0. Both are backed by a comparable volume of ratings — 4 and 11 respectively.
EngineCalc ships an update every 22 months, Rollout Calculator every 2 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.
| Parameter | EngineCalc | Rollout Calculator |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 3.0 (4 ratings) | 4.9 (11 ratings) — better |
| Positive reviews | 57.1% of reviews | — |
| Number of ratings | 4 | 11 — better |
| Update frequency | Every 22 months | Every 2 months — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Paid | Ad-supported — better |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 26.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 13 MB | 8 MB |
| Age rating | 4+ | 4+ |
| Developer | iTrinity, Inc. | Takao Ichimura |
Customer experience
EngineCalc
Rollout Calculator
In-app purchases
EngineCalc
No in-app purchases
Rollout Calculator
No in-app purchases
Questions
Is EngineCalc free?
Is Rollout Calculator free?
Which has better reviews, EngineCalc or Rollout Calculator?
Do EngineCalc or Rollout Calculator have ads?
Which is updated more often, EngineCalc or Rollout Calculator?
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