**Non-SI Units**

Click here for SI units
like meters, kilograms, and seconds. SI stands for *Syst�me
International*, which consists of the base units of length, mass,
temperature, time, and charge.

### Distance (length):

**Point:** 1/72 inch, as in 12-point type, which is 12/72, or 1/6 inches
tall.

**Inch:** exactly 0.0254 meters

**Hand:** 4 inches.

**Span:** 9 inches.

**Foot:** 12 inches.

**Cubit:** 18 inches.

**Yard:** 3 feet.

**Smoot:** 67 inches. It's a
long story.

**Fathom:** 6 feet.

**Rod:** 16.5 feet.

**Chain:** 66 feet, or 4 rods.

**Furlong:** 660 feet, or 1/8 mile.

**(Statute) Mile:** 5280 feet, or 1760 yards. A mile is exactly
12*5280 inches, which is exactly .0254*12*5280 meters, which is exactly 1609.344
meters.

**Nautical Mile:** once 6080 feet, now exactly 1852 meters, by
international agreement, which is 6 076.11549 feet.

**Cable:** 1/10 of a nautical mile.

**League:** 3 Nautical miles.

**Light year:** approximately 9.4605284 � 10^{15}
meters, the distance light travels in one year.

**Parsec:** approximately 3.08568025 � 10^{16} meters, or
3.26163626 light years

### Area:

**Acre** 43,560 square feet, or 1/640 square miles.

### Volume:

**[U.S.] Fluid Ounce:** about 0.0295735297 liters

**[U.S.] Pint:** 16 fluid ounces, about 0.473176475 liters, or about
4.73176475 � 10^{-4} cubic meters

**Imperial Fluid Ounce:** about 0.960760333 US fluid ounces, or about
0.0284130742 liters

**Imperial Pint:** 20 imperial fluid ounces, about 1.20095042 US pints,
0.568261485 liters, or 5.68261485 � 10^{-4} cubic meters

**Board foot:** 144 cubic inches, used to measure and express the amount
of wood in trees.

### Velocity (speed):

**Knot:** 1 nautical mile per hour

### Internet references

Wikipedia:
Units of length is a good place to learn about really obscure units of
length, such as the "beard-second". Even better: Wikipedia's
list of unusual units of measurement.

### Related pages in this website

Back to Physics home

The webmaster and author of this Math Help site is
Graeme McRae.