Convert units, currencies, time zones, number bases and more — instantly and accurately.
Which tool do I need?
- Convert length, weight, volume, area, speed or data sizes: Unit Converter
- Convert between Celsius, Fahrenheit and Kelvin: Temperature Converter
- Convert money between currencies at today’s rates: Currency Converter
- Find the time in another city, or plan a meeting across time zones: Time Zone Converter
- Convert numbers between binary, octal, decimal and hexadecimal: Number Base Converter
About these tools
Converters for the units and values people look up every day: length, weight, volume, area and speed; Celsius, Fahrenheit and Kelvin; the time in another city; binary, octal, decimal and hexadecimal; and currencies at the day’s exchange rates.
Results update as you type, and every converter shows the exact factor or formula it uses. The currency converter is the only one that downloads anything: the day’s rates, never the amounts you enter.
Frequently asked questions
Where do the exchange rates come from?
The currency converter downloads published daily reference rates when the page opens. They are mid-market rates, so a bank or card provider will usually give you slightly less. See how our calculators work for the details.
How precise are the unit conversions?
They use the exact international definitions (for example 1 inch = 2.54 cm and 1 pound = 0.45359237 kg) and show results to eight significant figures.
Do the converters work offline?
Yes, once the page has loaded, except the currency converter, which needs a connection to fetch the day’s rates.