List of humorous units of measurement

Many people have made use of, or invented, units of measurement intended primarily for their humour value. This is a list of such units invented by sources that are notable for reasons other than having made the unit itself, and of units that are widely known in the anglophone world for their humour value.

Conventional

These units may or may not have precise objectively measurable values, but all of them measure quantities that have been defined within the International System of Units.

Systems

FFF units

Most countries use the International System of Units (SI). In contrast, the humorous Furlong/Firkin/Fortnight system of units of measurement draws attention by being extremely old fashioned, and off-beat at the same time.

One furlong per fortnight is very nearly 1 centimetre per minute (to within 1 part in 400). Indeed, if the inch were defined as 2.54 cm rather than 2.54 cm exactly, it would be 1 cm/min. Besides having the meaning of "any obscure unit", furlongs per fortnight have also served frequently in the classroom as an example on how to reduce a unit's fraction. The speed of light may be expressed as being roughly 1.8 terafurlongs per fortnight (or megafurlongs per microfortnight).