Unit Converter

The units

Numbers and precision

• Type a decimal such as 12.5 or -0.003, or scientific notation such as 6.02e23 or 1.6e-19. What you type is read exactly: 0.1 is one tenth, not the nearest binary fraction.
• Every unit is defined by an exact number, and a conversion is carried out on fractions, with no rounded step in between. Only the last step rounds, to the number of significant digits you choose (not decimal places), half away from zero.
• A result that needs no more digits than that is shown as it is, and is exact. One that was rounded keeps all its digits, zeros included, and is marked with ≈.
• Numbers of 10¹⁵ and more, or below 10⁻⁷, are written in scientific notation. Copying gives a plain number such as 1.5e21.
• Swapping uses the exact result as the new quantity, so swapping back returns the number you started from.
• Temperatures are absolute temperatures: nothing below absolute zero is accepted.