Unit Converters

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.

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.

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.

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.

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.

Converting Between Measurement Systems That Rarely Agree

The world runs on at least two incompatible major measurement systems — metric and imperial — plus a handful of specialized units for pressure, energy, and data transfer that show up in specific technical contexts. Thirteen converters here handle the everyday and technical conversions that come up constantly across cooking, science, engineering, and international travel.

Popular Unit Converters

Highlights across everyday and technical conversions:

  • Length Converter — converts between metric and imperial length units, from millimeters to miles.
  • Weight Converter — converts between kilograms, pounds, ounces, and other mass units.
  • Temperature Converter — converts between Celsius, Fahrenheit, and Kelvin.
  • Volume Converter — converts between liters, gallons, cups, and other volume units.
  • Pressure Converter — converts between PSI, bar, pascal, and other pressure units used in engineering and weather reporting.

Why Temperature Conversion Isn't Just Multiplication

Unlike length or weight conversions, which are simple multiplication by a fixed ratio, temperature conversion between Celsius and Fahrenheit requires both a multiplication and an offset (°F = °C × 9/5 + 32), because the two scales don't share a common zero point — 0°C (freezing point of water) is 32°F, not 0°F. Kelvin adds a third reference point entirely, starting at absolute zero rather than water's freezing point, which is why scientific contexts default to Kelvin: it avoids negative numbers for any physically possible temperature and simplifies thermodynamic calculations that would otherwise need to account for an arbitrary offset.

Frequently Asked Questions

Why do US recipes and international recipes need volume conversion so often?
The US customary system measures cooking volumes (cups, tablespoons) that don't align cleanly with the metric measurements (milliliters, liters) used in most of the rest of the world, so recipe conversion is a common practical need.

Is a UK gallon the same as a US gallon?
No — the UK (imperial) gallon is larger than the US gallon, about 20% more volume, which is a common source of conversion errors when a "gallon" isn't specified as US or imperial.

Explore More

Converting units specifically for cooking? See the Cooking & Food Calculators, or check technical engineering conversions in the Civil Engineering Calculators.