CalcBoard / Unit Converter
A Unit Converter Built on Exact Decimal Math
79 units across 10 categories, converted with 18-digit decimal precision as you type — in a panel that can sit right next to the calculation that needs the answer.
Download CalcBoard Free10 categories, 79 units
| Category | Examples | Tier |
|---|---|---|
| Length (10 units) | m, km, cm, mm, µm, miles, yards, feet, inches, nautical miles | Free |
| Mass (7) | kg, g, mg, tonnes, pounds, ounces, stone | Free |
| Temperature (3) | Celsius, Fahrenheit, Kelvin | Free |
| Area (9) | m², km², acres, hectares, ft²… | Premium |
| Speed (5) | m/s, km/h, mph, knots… | Premium |
| Time (8) | seconds through years | Premium |
| Data (9) | kB–PB plus KiB, MiB, GiB | Premium |
| Volume (12) | liters, gallons, cups, tablespoons… | Premium |
| Energy (8) | joules, calories, kWh, BTU… | Premium |
| Pressure (8) | Pa, bar, psi, atm… | Premium |
The free tier isn't a demo: length, mass, and temperature — 13 everyday units — are free forever, with no ads.
Why exact math matters in a converter
Most converters run on floating-point arithmetic, which quietly mangles the last digits of a conversion. CalcBoard converts with decimal arithmetic at 18-digit precision, and temperature uses exact formula conversion rather than lookup approximations. What you see is the real number.
Convert in one panel, calculate in the next
The converter is a full panel mode, so the classic engineering workflow finally fits on a phone: convert 72 °F in one panel, use the Celsius result in a formula in the next panel, and keep a running total in a third. Results appear as you type, and the swap button flips the conversion direction instantly.
Frequently Asked Questions
Which unit categories are free?
Does CalcBoard convert currencies?
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Convert without the guesswork
Length, mass, and temperature free forever. 79 units with Premium.
Download Free on App Store