Unusual Units of Measurement
A guide to obscure, historical, and entertaining units of measurement that are still used today or hold an important place in measurement history.
Last updated: 2026-04-28
Unusual Length and Distance Units
Many measurement units that seem absurd today had very practical origins. The furlong was the standard length a team of oxen could plow before resting. The hand was the most convenient tool for measuring horses — literally, the width of four fingers. Even the smoot, a modern joke unit, has been immortalized on the Harvard Bridge in Cambridge, MA, where the markings are repainted each year.
| Unit | Metric Value | Imperial Value | Still Used? |
|---|---|---|---|
| Smoot | 170.18 cm | 5 ft 7 in | Harvard Bridge markings, Google Maps (briefly) |
| Hand | 10.16 cm | 4 in | Yes — horse height measurement worldwide |
| Barleycorn | 8.47 mm | ⅓ inch | UK shoe size increments are 1 barleycorn apart |
| Chain | 20.1168 m | 66 ft / 22 yards | Yes — land surveying, cricket pitch |
| Rod / Pole / Perch | 5.0292 m | 16.5 ft / 5.5 yards | Historic land surveying |
| Furlong | 201.168 m | 660 ft / 220 yards | Yes — horse racing internationally |
| League | 4.828 km | 3 miles | Historic; “20,000 Leagues Under the Sea” |
| Fathom | 1.8288 m | 6 ft | Yes — nautical depth measurement |
Unusual Weight and Volume Units
| Unit | Metric Value | Imperial Value | Still Used? |
|---|---|---|---|
| Stone | 6.35029 kg | 14 lbs | Yes — body weight in UK and Ireland |
| Hundredweight (US) | 45.36 kg | 100 lbs | Agriculture and shipping in the US |
| Hundredweight (UK) | 50.80 kg | 112 lbs | Declining but still referenced in UK |
| Hogshead (US) | 238.48 L | 63 US gallons | Tobacco and whiskey aging barrels |
| Firkin | ~9 L | ~2.25 US gallons | Artisan brewing, butter measurement |
| Bushel (US) | 35.24 L | 8 dry gallons | Grain trading in the US |
| Peck | 8.81 L | 2 dry gallons | “A peck of pickled peppers” — ¼ bushel |
Why These Units Persist
Some unusual units survive because industries built entire infrastructure around them. Horse racing adopted furlongs and they remain the international standard for race distances. The stone persists in British culture for body weight because it gives convenient single- and double-digit numbers for most adult weights. The chain survives in surveying because 10 chains equal exactly 1 furlong, 80 chains equal 1 mile, and an area of 10 square chains equals 1 acre — relationships that made fieldwork arithmetic manageable before calculators.
Use our length converter, weight converter, and volume converter to explore these unusual units alongside metric equivalents.