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 · Ancient Egyptian · Middle Kingdom/New Kingdom and later
khet
range
- Record
- M157
- Definition quality
- Historically documented
- Conversion mode
- range
- Calculator
- Range only
Definition
1 khet = 100 royal cubits; with 52.5 cm cubit ≈52.5 m
Documented range
Surviving evidence places one khet between 52.3 and 52.9 metres. It is recorded as a range because the documented values were not uniform.
History & use
The Rhind Mathematical Papyrus uses the khet in land-measurement problems; one square khet forms the setat area unit.
Modern use
Modern use is context-dependent and varies by region or measurement system.
Sources & evidence
Source tier — · confidence high
- Fr. Monnier, J.-P. Petit, Chr. Tardy, Journal of Ancient Egyptian Architecture 1 — https://www.egyptian-architecture.com/JAEA1/JAEA1_Monnier_et_al.html
- Museo Egizio, Turin — https://collezioni.museoegizio.it/en-GB/material/Cat_6347
- Arnold Buffum Chace, with L. Bull, H. P. Manning and R. C. Archibald; Mathematical Association of America — https://upload.wikimedia.org/wikipedia/commons/7/7b/The_Rhind_Mathematical_Papyrus%2C_Volume_I.pdf
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.
yard
ydlength · UK / US · Modern / historical
1 international yard = exactly 0.9144 m.
mile
milength · UK / US · Modern / historical
1 international mile = exactly 1609.344 m = 1760 yd.