Caliper01 / Length
The base unit used here is the metre. Inch, foot, yard and mile refer to the international definitions. Multiply by the factor below to obtain metres.
| Unit | Symbol | Metres per unit |
|---|---|---|
| Millimetre | mm | 0.001 |
| Centimetre | cm | 0.01 |
| Metre | m | 1 |
| Kilometre | km | 1,000 |
| Inch | in | 0.0254 |
| Foot | ft | 0.3048 |
| Yard | yd | 0.9144 |
| Mile | mi | 1,609.344 |
All factors in this table are exact definitions. Survey feet and nautical miles are outside this calculator’s scope.
02 / Mass
The base unit used here is the kilogram. Ounce and pound mean avoirdupois mass; they are not troy units or fluid measures.
| Unit | Symbol | Kilograms per unit |
|---|---|---|
| Milligram | mg | 0.000001 |
| Gram | g | 0.001 |
| Kilogram | kg | 1 |
| Tonne | t | 1,000 |
| Ounce | oz | 0.028349523125 |
| Pound | lb | 0.45359237 |
These factors are exact. A tonne is a metric tonne, not a US short ton or an imperial long ton. Weight is a force; this table converts mass.
03 / Pressure
The base unit used here is the pascal: one newton per square metre. The calculator changes the unit while retaining the original pressure reference.
| Unit | Symbol | Pascals per unit |
|---|---|---|
| Pascal | Pa | 1 |
| Kilopascal | kPa | 1,000 |
| Megapascal | MPa | 1,000,000 |
| Bar | bar | 100,000 |
| Pound-force per square inch | psi | ≈ 6,894.75729317 |
| Standard atmosphere | atm | 101,325 |
| Torr | Torr | 101,325 / 760 |
The psi factor shown is rounded; the calculator derives it from the international pound, standard gravity (9.80665 m/s²) and the international inch. The other definitions are exact.
Gauge or absolute? A gauge measurement is relative to a reference pressure, usually ambient atmospheric pressure. Converting bar to psi does not add that reference. A standard atmosphere is a defined unit, not a reading of the local weather.
04 / Temperature
Temperature scales require an offset as well as a scale factor. The calculator works with absolute temperatures, not differences between two readings.
°F = (°C × 9/5) + 32
°C = (°F − 32) × 5/9
| Checkpoint | Celsius | Fahrenheit / kelvin |
|---|---|---|
| Absolute zero | −273.15 °C | −459.67 °F / 0 K |
| Zero Celsius | 0 °C | 32 °F / 273.15 K |
| Equal numeric reading | −40 °C | −40 °F / 233.15 K |
For temperature differences, omit the offset: a change of 1 °C equals a change of 1 K or 1.8 °F. Do not enter a temperature difference into the absolute-temperature converter.