Unit Converter

A unit converter translates a measurement from one unit to another within the same physical category (you can't convert weight to length, for example). The tool uses internationally-standardised SI ratios as its reference, with precision sufficient for engineering and accounting use.

How the calculation works

Each category has a reference base unit (e.g. metre for length, kilogram for weight). Conversion goes through that base: input → base → target.

Result = (input × source factor) ÷ target factor

Worked example

Converting 5 kilograms to pounds:

1. Input: 5 kg
2. Reference unit: the kilogram (factor 1)
3. Pound factor = 0.45359237 kg
4. Result = 5 ÷ 0.45359237 = 11.0231 lb

Supported categories

• Length: mm, cm, m, km, in, ft, yd, mi, nautical mile.
• Weight: mg, g, kg, t, oz, lb, stone.
• Volume: mL, L, m³, US/UK gallon, fl oz, cup, tsp, tbsp.
• Temperature: Celsius (°C), Fahrenheit (°F), Kelvin (K).
• Area: mm², cm², m², ha, km², ft², yd², acre, mi².
• Speed: m/s, km/h, mph, knot, ft/s.
• Pressure: Pascal, kilopascal, bar, atmosphere, PSI, mmHg.
• Energy: Joule, kilojoule, calorie, kcal, watt-hour, kWh, BTU.

Units whose size changes with the market

• The gallon: 3.785 litres in the US and 4.546 imperial — a 20% gap under the same name, and it shows up in fuel and liquid contracts.
• The tonne: 1,000 kg metric, 907 kg short, 1,016 kg long — check which one your contract means before pricing.
• The feddan: about 4,047 m² internationally and about 4,200 m² by the traditional Egyptian measure — enough to change a land area outright.
• The ounce: the ordinary weight ounce differs from the troy ounce used for precious metals — confusing them is a pricing error, not a conversion one.