Comparison

Engineer's Unit Converter vs HydroCalc

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

Head to head
About

Engineer's Unit Converter

Features
Read full description

A unit converter built for engineering work rather than for the kitchen. Thirty-two categories, from the everyday ones to the specialist tables you normally go looking for in a handbook: AWG wire gauge, tons of refrigeration, viscosity, water hardness, radiation dose, moment of inertia. EVERY CATEGORY, ALL FREE Length, Area, Pressure/Stress, Mass/Weight, Energy/Work, Power, Force, Torque, Volume, Temperature, Time, Speed, Angle, Data, Frequency, Fuel Economy, Density, Flow, Viscosity, Acceleration, Electric Current, Voltage, Resistance, Electric Charge, Magnetic Flux Density, HVAC Cooling, Water Hardness, Radiation Activity, Radiation Dose, Radiation Equivalent Dose, Moment of Inertia, Wire Gauge. No unlocks, no ad to watch first, no timer. Every category above is open the moment you install. ENGINEERING TOOLS An expression calculator that accepts arithmetic, fractions and scientific notation, so you can type 3/8 or 1.2e-3 straight into the field. An HVAC sizing helper that turns tons of refrigeration into BTU/h, kW and rule-of-thumb airflow. Reference tables for physical constants, thermocouple types and hardness scales. BUILT FOR THE JOB Works fully offline, so it does not care about signal on site. Reads decimal commas and points the way your region writes them. Pin the units you use, hide the ones you never touch, and reorder the rest. Add your own units with a conversion factor. Every conversion is kept in a searchable history you can tap to reuse. No account, no sign-in, no data leaves the device.

About

HydroCalc

Features
Read full description

HydroCalc is a calculation aid for heating and HVAC technicians. Calculate flow from heat output and temperature difference alongside the existing hydraulic calculators. CIRCUIT PROJECTS Create named projects and group circuits by room, category or floor. Record heat output, temperature difference and input sources for each circuit. View total heat output and required flow together. BASELINE AND COMPARISON Capture a fixed baseline and edit later proposals independently. Review differences in totals and share a calculation worksheet with inputs, sources and comparison. German and English. Local projects and calculations work offline. Existing purchase unlocks remain available. Professional calculation aid: manufacturer data, applicable rules, system design and actual measurements take precedence. Check results against the real installation. EULA: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Engineer's Unit Converter4 screens
HydroCalc3 screens

Verdict

The call

The clearest difference is ads: HydroCalc at none against Engineer's Unit Converter's shown. Engineer's Unit Converter's advantage is update cadence (monthly vs every 2 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

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

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. Engineer's Unit Converter sells 1 one-off in-app purchase and HydroCalc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Engineer's Unit Converter ships an update monthly, HydroCalc every 2 months. The most recent releases landed on October 26, 2026 and October 25, 2026 respectively.

Scorecard2 real differences ยท 4 level
Engineer's Unit Converter versus HydroCalc: the parameters behind the verdict, then further details
ParameterEngineer's Unit ConverterHydroCalc
PriceFreeFree
Update frequencyMonthly โ€” betterEvery 2 months
AdsYesNo โ€” better
In-app purchasesYesYes
DevicesiPhone, iPadiPhone, iPad
Requires iOS18.017.0 โ€” better
Further details โ€” not scored
Size7 MB1 MB
Age rating4+4+
DeveloperJose Gerardo Palma DuranPiotr Kaminski

In-app purchases

1 purchases

Engineer's Unit Converter

One-time1
  • Remove Ads$0.99
1 purchases

HydroCalc

One-time1
  • HydroCalc Pro$3.99

Questions

Is Engineer's Unit Converter free?
Engineer's Unit Converter is free to download, with in-app purchases available.
Is HydroCalc free?
HydroCalc is free to download, with in-app purchases available.
Do Engineer's Unit Converter or HydroCalc have ads?
Engineer's Unit Converter shows ads; HydroCalc does not.
Which is updated more often, Engineer's Unit Converter or HydroCalc?
Engineer's Unit Converter ships an update monthly, and HydroCalc every 2 months. Most recently, Engineer's Unit Converter was updated on October 26, 2026 and HydroCalc on October 25, 2026.

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