Non-SI unit accepted for use with SI
Name Symbol Quantity Value in SI units
tonne t mass 1 Mg
103 kg


The tonne, symbol t, is a non-SI unit of mass accepted for use with the SI.
One tonne is equal to 1000 kilograms, or 1 megagram.

For everyday use, one cubic metre of water has a mass of one tonne.

The tonne is the unit of mass used on international standard road traffic signs.


The symbol T is the SI symbol for the tesla, and should not be used as a symbol for tonne.

The symbol for tonne, t, should always be on the line, e.g. 7.5 t, and not written as a superscript.