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## User Guide

This metric, imperial and si unit length measuring converter and conversion scale can be used to convert any measurement of length from one unit of length to another.

### Conversion Factors

The following units and associated conversion factors in metres (SI units for length) are used by this length converter:

#### SI Metric Prefix Length Units

- yoctometre (ym) – 1 x 10
^{-24}m - zeptometre (zm) – 1 x 10
^{-21}m - attometre (am) – 1 x 10
^{-18}m - femtometre (fm) – 1 x 10
^{-15}m - picometre (pm) – 1 x 10
^{-12}m - nanometre (nm) – 1 x 10
^{-9}m - micrometre (µm) – 0.000001 m
- millimetre (mm) – 0.001 m
- centimetre (cm) – 0.01 m
- decimetre (dm) – 0.1 m
- metre (m) – 1 m
- decametre (dam) – 10 m
- hectometre (hm) – 100 m
- kilometre (km) – 1,000 m
- megametre (Mm) – 1,000,000 m
- gigametre (Gm) – 1 x 10
^{+9}m - terametre (Tm) – 1 x 10
^{+12}m - petametre (Pm) – 1 x 10
^{+15}m - exametre (Em) – 1 x 10
^{+18}m - zettametre (Zm) – 1 x 10
^{+21}m - yottametre (Ym) – 1 x 10
^{+24}m

#### Imperial and US Length Units

- thousandth of an inch (thou) – 0.0000254 m
- inch (in) – 0.0254 m
- foot (ft) – 0.3048 m
- yard (yd) – 0.9144 m
- mile (mi) – 1,609.344 m
- nautical mile (nmi) – 1,852 m

#### Astronomical Units

- astronomical unit (au) – 149,597,870,700 m
- light-year (ly) – 9,460,730,472,580,800 m
- parsec (pc) – 30,856,775,814,913,672.789… m
- kiloparsec (kpc) – 3.0856775814913672789… x 10
^{+19}m - megaparsec (Mpc) – 3.0856775814913672789… x 10
^{+22}m - gigaparsec (Gpc) – 3.0856775814913672789… x 10
^{+25}m

## Tool Help

### How precise is the conversion?

The converted answer is displayed to a precision of 9 significant figures

### What does an answer that looks like 2.67e+16 mean?

These are standard form numbers, which are used when there too many zeros either size of the decimal point, therefore a length that is displayed as 2.67e+16 is short for 2,670,000,000,000,000,000 or 6.898e-8 is short for 0.00000006898.

### Convert cable length to nautical miles

*What is cable length? One cable is equal to how many nautical miles?*

1 cable length (international) = 1/10 nautical mile (international)

It is an obsolete unit of length, this glossary of nautical measures explains a little of the history of the cable length.