Unit Conversion Calculator

This converter covers 24 categories used across mechanical engineering — from the everyday (length, mass, area) to the more specialised (torque, viscosity, moment of inertia). Pick a category from the dropdown, enter a value in either box, and the other box updates instantly with the converted result.

Full list of categories covered: Acceleration, Angle, Angular Acceleration, Angular Velocity, Area, Density, Energy, Force, Force/Length, Length, Mass, Mass Flow, Moment of Force, Moment of Inertia, Power, Pressure and Stress, Temperature, Tensile Strength, Torque, Velocity and Speed, Dynamic Viscosity, Kinematic Viscosity, Volume & Capacity, and Volume Flow.

It's really quick and easy to use, firstly, select your conversion type from the dropdown menu, then enter a value to convert in either box A or B.

Secondly, select your conversion from and to types and your result will show instantly; told you it's really easy to use.

FREQUENTLY ASKED QUESTIONS

Why are Torque and Energy separate categories when both use newton-metres?

Torque and energy are dimensionally identical (both reduce to N·m) but are physically different quantities — torque is a rotational force acting around an axis, while energy is a scalar measure of work done. Keeping them separate avoids the common mix-up between, for example, a torque spec of "300 lb-ft" and an energy value of "300 ft-lb," which use the same numbers but mean different things.

Why do some units, like BTU or the gallon, appear more than once?

Several everyday units have more than one historical definition — there's a US gallon and a UK (imperial) gallon, and different BTU definitions (mean, thermochemical) that vary slightly from each other. Where this applies, each variant is listed separately and labelled, rather than picking one silently, since the differences (the US/UK gallon differs by around 20%) are large enough to matter in a real calculation.

Does the temperature conversion handle the offset between scales correctly?

Yes — temperature is the one category here that needs an offset as well as a multiplying factor (since 0°C isn't 0°F or 0K), and this is handled automatically so you can convert directly between Celsius, Fahrenheit, Kelvin, and Rankine.

What's the difference between "Mass Flow" and "Volume Flow"?

Mass Flow (kg/s, lb/min, etc.) measures how much mass moves past a point per unit time; Volume Flow (m³/s, L/min, US/UK gallons per minute, cfm, etc.) measures how much volume moves past a point per unit time. The two are only related once you know the fluid's density, so make sure you're converting within the correct category for what you actually need.

RELATED PAGES

• SI Units
• Material Strength
• Engineering Glossary