length · International · Modern
SI base unit of length. Its definition fixes the speed of light in vacuum at exactly 299,792,458 m/s, with the second defined from the caesium-133 hyperfine frequency.
Converter
length · UK / US · Modern / historical
yard
ydexact
- Record
- M048
- Definition quality
- Standardized
- Conversion mode
- multiplicative
- Calculator
- Fully calculable
Definition
1 international yard = exactly 0.9144 m.
Reference value
One yard is equal to 0.9144 metres.
History & use
The international yard was adopted in 1959 by the United States and several Commonwealth countries.
Modern use
Current-use record in the project inventory; exact scope should follow the definition and regional/system context shown here.
Did you know?
The exact yard definition simultaneously fixed the international foot and inch.
Sources & evidence
Related measurements
length · International · Modern
1 km = 1000 m by the SI prefix kilo-.
length · International · Modern
1 cm = 0.01 m by the SI prefix centi-.
length · International · Modern
1 mm = 0.001 m by the SI prefix milli-.
inch
inlength · UK / US · Modern / historical
1 international inch = exactly 0.0254 m.
foot
ftlength · UK / US · Modern / historical
1 international foot = exactly 0.3048 m.
mile
milength · UK / US · Modern / historical
1 international mile = exactly 1609.344 m = 1760 yd.
length · UK / US · Modern / historical
1 international nautical mile = exactly 1852 m.