Comparison

Engineer's Unit Converter vs PlantCalculator

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

Head to head
About

Engineer's Unit Converter

Features
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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

PlantCalculator

Features
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The nameplate reads "52.7 kg/cm²G." Your reference is in psi. The formula wants MPa. You can stop doing that conversion in your head. Plant Calculator brings together the calculations used every day in refinery and chemical plant equipment inspection — one app, built for the field. ■ Type the number on the nameplate, as-is Every input field has a unit selector. Enter kg/cm²G, psi or bar exactly as written, and the app does the conversion. If you think in kg/cm², set it as your default in Settings and every screen opens that way. 15 categories, 65 units. ■ Works where there's no signal Inside a vessel, inside a tank — every calculation runs entirely on your device. ■ Enter only what you already know - Pick a nominal size and schedule, and OD and wall are filled in (ASME/JIS, 45 sizes) - Pick a material and temperature, and the allowable stress is interpolated and filled in (9 materials) No more flipping through dimension tables. ■ Main features - Quick Check: from pipe and inspection data, review original wall, required thickness, corrosion rate, remaining life and thickness margin together - Required thickness: minimum wall for piping and pressure vessels under internal pressure (JIS B 8265 / High Pressure Gas (KHK), ASME Sec.VIII Div.1, ASME B31.3; cylinders, heads, straight pipe and elbows) - Corrosion rate & remaining life from previous/current thickness and elapsed years - Metal loss check: average, minimum and variation from readings, with simplified general and local metal-loss checks - Vertical tower check: internal pressure, dead weight, wind and seismic (static seismic coefficient method); checks tension and compression for operating and shutdown cases and shows a reference thickness. Skirt included - External pressure: simplified allowable external pressure check for cylinders - Nozzle reinforcement: area replacement method - Relief valve sizing: required orifice area based on API 520 - Piping: support span, pressure drop and velocity - Vessel: flange, bolt torque, flat plate, cone and support loads - Surface area: outer area of pipe, elbow, head and reducer; add count and insulation thickness for painting/cladding area and a material estimate - Tank / line totals: connect elements to sum area, volume and weight - Thermal expansion from temperature difference - Calculator + equation solver: scientific calculator (trigonometry, logs, powers, roots, memory, EE input, DEG/RAD) that also solves simultaneous equations in x, y and z - Unit conversion: 15 categories, including multiplication and division with units (e.g. 200 mm × 200 mm = 0.04 m²) - Size quick reference: NPS to OD, wall, ID, volume and pipe weight - Pipe dimension lookup: pick a size to see OD and wall per schedule (ASME B36.10M/B36.19M / JIS, physical dimension reference values) - Flange rating check: enter the rated pressure from your standard and compare with design pressure (ASME B16.5, etc.; rating table not bundled) - Material list: temperature-dependent allowable stress reference values (based on High Pressure Gas example standards) - Glossary for inspection and design terms - Calculation history: save, delete and copy as CSV - 8 languages (Japanese, English, Español, Português, 한국어, Deutsch, العربية, Русский), dark mode ■ Important This app is a supporting tool for design and inspection. Formulas are representative, and allowable stresses, dimensions and ratings are approximate reference values. Always verify against the official formulas and latest values of the applicable codes (JIS B 8265 / High Pressure Gas example standards / ASME Sec.II Part D / B16.5 / B36.10M, etc.) before making any decision. Do not rely on this app's results alone.

Screenshots

Engineer's Unit Converter4 screens
PlantCalculator4 screens

Verdict

The call

The clearest difference is in-app purchases: PlantCalculator at none against Engineer's Unit Converter's 1. PlantCalculator also leads on update cadence (every 9 days vs monthly) and iOS requirement (13.0 vs 18.0). On price, ads and device support 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

Both are free to download. Engineer's Unit Converter sells 1 one-off in-app purchase. PlantCalculator asks for nothing beyond the download.

UpkeepUpdate frequency

Engineer's Unit Converter ships an update monthly, PlantCalculator every 9 days. Both last shipped on October 31, 2026.

Scorecard3 real differences · 3 level
Engineer's Unit Converter versus PlantCalculator: the parameters behind the verdict, then further details
ParameterEngineer's Unit ConverterPlantCalculator
PriceFreeFree
Update frequencyMonthlyEvery 9 days — better
AdsYesYes
In-app purchasesYesNo — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS18.013.0 — better
Further details — not scored
Size7 MB25 MB
Age rating4+4+
DeveloperJose Gerardo Palma DuranRyo Iida

In-app purchases

1 purchases

Engineer's Unit Converter

One-time1
  • Remove Ads$0.99
None

PlantCalculator

No in-app purchases

Questions

Is Engineer's Unit Converter free?
Engineer's Unit Converter is free to download, with in-app purchases available.
Is PlantCalculator free?
PlantCalculator is free to download, with no in-app purchases.
Do Engineer's Unit Converter or PlantCalculator have ads?
Both Engineer's Unit Converter and PlantCalculator show ads.
Which is updated more often, Engineer's Unit Converter or PlantCalculator?
Engineer's Unit Converter ships an update monthly, and PlantCalculator every 9 days. Most recently, Engineer's Unit Converter was updated on October 31, 2026 and PlantCalculator on October 31, 2026.

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