Unit Converters

Angle Unit Converter

Convert angle measurements between degrees, radians, and gradians for math, engineering, and surveying applications.

Area Converter

Convert square feet, square metres, acres and hectares with correctly squared length factors, an exact factor table and land parcel and floor area figures.

Cooking Volume Converter

Convert cooking and baking measurements between US cups, tablespoons, teaspoons, and milliliters.

Data Storage Converter

Convert digital storage capacity between bytes, kilobytes, megabytes, gigabytes, and terabytes using binary (1024-based) units.

Data Transfer Rate Converter

Convert Mbps, MB/s, Gbps and other data rates, and see exactly why a 100 Mbps line downloads at only 12.5 MB/s, with a full bit-to-byte cross-reference table.

Density Unit Converter

Convert density values between kilograms per cubic meter, grams per cubic centimeter, and pounds per cubic foot.

Energy Conversion Calculator

Convert joules, calories, food kilocalories, kilowatt-hours, BTU and foot-pounds with exact factors, plus a one-kilowatt-hour comparison across six units.

Fuel Economy Unit Converter

Convert vehicle fuel economy between miles per gallon (US), liters per 100 kilometers, and kilometers per liter.

Geometry Area Converter

Convert a calculated shape area into any area unit, with the shape formulas that feed it, correctly squared factors and a complete unit reference table.

Length Converter

Convert metres, feet, inches, yards, miles and kilometres using the exact 1959 factors, with a full cross-reference table and the pivot formula explained.

Oven Temperature Converter

Convert oven temperatures between Fahrenheit, Celsius and British gas marks using the standard gas mark reference table and its irregular low-end steps.

Power Conversion Calculator

Convert watts, kilowatts, mechanical horsepower and metric PS, which differ by 1.4 percent, with exact factors and a horsepower to kilowatt reference table.

Pressure Converter

Convert PSI, bar, pascal, atmospheres, mmHg and inHg using defined constants, with a factor table plus one-atmosphere and tyre pressure reference figures.

Speed Converter

Convert mph, km/h, m/s, knots and ft/s using exact defined factors, with a full cross-conversion table and speed limit equivalents for road and air travel.

Temperature Converter

Convert Celsius, Fahrenheit, Kelvin and Rankine with the exact offset formulas, absolute-zero guard rails and a side-by-side four-scale reference table.

Time Unit Converter

Convert time durations between seconds, minutes, hours, days, and weeks using simple fixed multipliers.

Torque Unit Converter

Convert torque values between newton-meters, foot-pounds, and inch-pounds for automotive, tool, and engineering specifications.

Volume Converter

Convert litres, US and imperial gallons, quarts, pints and cups, keeping the two gallon systems strictly apart, with kitchen and fuel reference tables.

Volume Unit Converter

Convert cubic feet, cubic metres, litres, gallons and barrels on a single scale, with the cubed factors explained and a full twelve-unit reference table.

Weight Converter

Convert kilograms, pounds, ounces, stone and tons using the exact 0.45359237 pound definition, with factor tables and body weight reference figures in stone.

The Same Number, in a Different Language

Every measurement system — metric, imperial, and the dozens of specialized units in between — describes the same underlying physical quantities, just in different-sized units. These thirteen calculators convert between them.

Why unit conversion is not a trivial detail: in 1999, NASA lost the $327 million Mars Climate Orbiter because one engineering team's software calculated thruster performance in pound-force seconds while the navigation team's software expected the figure in newton-seconds — a metric-versus-imperial mismatch that went unnoticed until the spacecraft burned up in the Martian atmosphere instead of entering orbit. It remains one of the most cited real-world examples of why unit conversion deserves the same rigor as any other calculation, at any scale. The Length Converter and other tools here exist to make that conversion explicit rather than assumed.

Popular Unit Converters

  • Temperature Converter — converts between Celsius, Fahrenheit, and Kelvin.
  • Weight Converter — converts between kilograms, pounds, ounces, and other mass units.
  • Pressure Converter — converts between pascals, PSI, bar, and other pressure units.

Related: Math Calculators, Physics Calculators for the science these units describe.