Ancient and non-metric measures

Measurement Systems

Used as we are to the SI (Systeme Internationale) methods of calculations, school exams in the late 1960s were taken in the fps system (foot-pound-second) and in the cgs (centimetre, gram, second). The SI system was then coming into use and was originally called the kms (kilogram, metre, second) system. We are  fortunate that no-one has redefined the second, minute, hour, day or year, although the exact duration has been recalculated, but the differences are small indeed. Although in this country schools teach in metric, when pupils come into everyday life they have to revert to imperial for the calculation of distances and speeds. (miles between locations and legal speeds in miles per hour). How a mile is made up is not overclear. If, however, you’re working in the oil and gas drilling industry in the North Sea then units current in the U.S.A. apply. In other words we’re back to feet and inches. But for the purposes of completeness, this is the equivalent table that we have found necessary (and a couple that we have discovered) in undertaking this research.

Linear measure

Unit Dimension Metric Comment
thou or mil 1/1000 inch 0.0254mm Term used in precision engineering
Inch (in) 25.4mm
Foot (ft) 12 Inches 304.8mm
Yard (yd) 3 feet 0.9144m
Fathom 6 feet 1.8288m Nautical and mining term for depth. Also used at surface for linear
Rod 5½ yards 5.0292m see also area and volumetric measure
Pole 5½ yards 5.0292m see also area and volumetric measure
Perch 5½ yards 5.0292m see also area and volumetric measure
Virgate 5½ yards 5.0292m see also area measure
Chain 22 yards or 4 rods, poles or perches 20.1168m Now used as a measure of a cricket pitch and on the railway system and is recognised by the EU. (Credit to Mike)
Cable 100 fathoms officially 182.88m Nautical term for horizontal distance
Cable (Royal Navy) 608ft 185.319m
Cable (international agreement) 1/10 international nautical mile 185.2m
Furlong 220 yards, or 40 rods, or 10 chains 201.168m The only common use is in horse racing. Wikipedia article about the furlone and its relationship to the acre – all to do with oxen and ploughing.
Statute Mile 1760 yards 1.6093 km Wikipedia article about miles and their variants
Nautical Mile (British) 6080 feet 1.853184 km
Nautical Mile (International) 1.150779 statute miles 1.852 km Length of a minute of longitude at the equator
60 Nautical Miles 1 degree of great circle of earth 111.12 km

Area Measure

Unit Dimension Metric Comment
square inch 6.452 sq cm
square foot 929.03 sq cm
square yard 0.8361 sq m
square rod 5½ x 5½ yards, 30.5 sq yds 25.292 sq m or rod, context defines
square pole 5½ x 5½ yards, 30.5 sq yds 25.292 sq m or pole, context defines
square perch 5½ x 5½ yards, 30.5 sq yds 25.292 sq m or perch, context defines
virgate 5½ x 5½ yards, 30.5 sq yds 25.292 sq m obsolete measure, see also rod, pole, perch. See also virgate below
hide Saxon measure. The amount of land necessary to support one family.
Used in recording in the Domesday Book. Variable. Also see hide
acre 160 sq rods or 4840 sq yd 0.4047 ha In mediaeval times 1 Cornish acre was equivalent to 60 English
acres. Exactly when Cornwall adopted the English Acre is undefined,
but certainly in the 14th and 15th centuries land measures were often
given as so many acres Cornish or so many acres English. The most
easily obtained document which exemplifies this is the Caption of
Seisin for the Duchy of Cornwall – 1337. Thanks to Patrick E
Coleman for this information.
arpent ~ 1 acre Old French term, measure of vinyeards. Still used in parts of
square furlong 10 acres
virgate 30 acres 12.141 ha An obsolete measure of land. ¼ hide See also virgate above.
yoke ¼ sulung Kentish measure
hide 120 acres varied between ~60 and ~240 acres. The area able to be cultivated by team of eight oxen in a year. Also carucate in the area of the Danelaw.
sulung 2 hides Kentish measure
square mile 640 acres 2.590 sq km
rood either square rod or ¼ acre ??? definition differs by source
hectare 100m x 100m, 2.471 acres 0.01 sq km

Cubic Measure

Unit Dimension Metric Comment
cubic inch 16.387 cc
cubic foot 1728 cubic inches 0.0283 cu m A cubic foot of water weighs 62½ pounds
cubic yard 27 cubic feet 0.7646 cu m
perch 24.75 cu ft 0.700425 cu m a stone measure 198 inches x 18 inches x 12 inches,16½ ft x 1½ ft x 1ft. A dimensioned quantity, not just any old volume. The context will define. 16½ ft is 5½ yd, the value of a linear perch

U.K. Volume Measure, liquids or solids

Unit Dimension Metric Comment
Minim 0.0038 cu in 0.0616 ml liquids only
fluid dram 60 minims, 0.2256 cu in 3.6966 ml liquids only
fluid ounce 8 fluid drams 0.0296 litre weighs the same as a solid ounce
gill 5 fluid ounces, ¼ pint 0.148 litre sometimes ghyll
noggin about ¼ pint approximate unit of capacity
pint 20 fluid ounces, 4 gills 0.568 litre A pint of pure water weighs a pound and a quarter
quart 2 pints 1.136 litre
pottle 4 pints 2.272 litre half a gallon – known in Tudor times.
gallon 4 quarts, 8 pints 4.456 litre A gallon of water weighs 10 lb
peck 2 gallons 9.092 litre
bushel 4 pecks, 8 gallons 36.37 litre A bushel is about the capacity of a normal gardener’s wheelbarrow (see below)
firkin 9 gallons 40.104 litre Also a wooden barrel of the same capacity
barrel 36 gallons 160.416 litre Brewing measure, 4 firkins.
hogshead 52½ gallons 233.94 litre Wine measure
hogshead 54 gallons 240.624 litre Beer measure, 6 firkins.
chaldron 36 bushels 1.309 cubic metres In the U.S. 1.268 cubic metres. An allowance on taxation of 4s per chaldron of coal was made for Cornish mining ventures during the eighteenth century.

U.S. Volume Measure

Unit Dimension Metric Comment
fluid ounce 0.0296 litre equal to imperial measure
pint 16 fluid ounces 0.4736 litre
U.S. gallon 8 U.S. Pints 3.785 litre A U.S. gallon is 20% less then a U.K. gallon
barrel (oil) 42 US gallons 159 litre equivalent 35 Imperial Gallons

Message from John Watts, BSc, a Lincolnshire farmer, on 18th January 2000

Only yesterday was discussing how we used to measure corn, in coombs and quarters. A coomb is four bushels, and a quarter eight. Commercially, the bags used were “Railway Bags”, i.e. hired from the railway companies at a penny (old) a week each; when you sold the corn the merchant took over the sack hire and gave you a dated chit to say so, and your bill was settled for the length of time the bags were in your possession, filled or not. By convention, these large sacks held one coomb volume, and the weights for various grains were:

  • Beans (dense stuff), 22 stones weight
  • Wheat (fairly heavy) 18 stones
  • Barley (Not so heavy) 16 stones
  • Oats (the lightest grain)12 stones.

So a quarter of wheat, i.e. two railway bags, weighed 4.5 cwt., of barley4cwt., and of oats 3cwt. Sounds complicated, but you got used to it.

Grain for our own use (before bulk storage) we put into old cattle-feedbags holding about ten stones of wheat or eight stones (1 cwt.) of barley. Easier to lift.

After B.R. (British Railways, formed after railway nationalisation on 1st January 1948 as a results of the Transport Act 1947) ceased to supply sacks such firms as Chisolm, Fox, and Garner began to set up in Sack Hire. My father-in-law, a threshing contractor, was agent for such a firm. My brother has an 8mm. film commissioned by the above firm when bulk combines and silos were just coming in, about 1960. It purports to show that hired sacks are the best and cheapest way of storing and transporting cereals, and features lorries and warehouses and ships bulging with thumping great sacks of corn, – it makes your hernia throb just to look at it.

Sacks are not heard of nowadays, and not much regretted, they did nothing for your spine and were prone to get rat-infested. When “bulk” took over,grain began to be traded by the ton and hundredweight, which was not hard to adapt to. But in recent years it has had to be kilos and tonnes, which are hard for us oldies to visualise, as are the hectares, metres, and litres.

O tempora, o mores. (Cicero)


Weight (Avoirdupois)

Unit Dimension Metric Comment
grain (gr) 0.0648 g equivalent in all three imperial tables of weight
dram (dr) 27.34 grains, 1/16 oz 1.772 g
ounce (oz) 16 drams, 437.5 grains 28.3495 g The abbreviation is from the Latin for pound, “libra”. This comes from the Latin “librare”, to balance or “libratus” meaning scales. It came into use about the 14th Century in Britain when weights were beginning to be standardised at 16 ounces to the pound.
pound (lb) 16 oz, 7000 grains 453.59 g
pound ** 18 oz 510.29 g Refining weight of Devon tinners
stone 14 lb 6.35 kg
quarter (qtr or QR) 2 stone, 28 lb 12.7 kg
quintal 100lb 45.4kg Archaic use. In the current metric system, 100kg.
hundredweight (cwt) 112 lb 50.8 kg
hundredweight ** 112lb 57.15 kg based on 18 oz pound, 126 16 oz pound
thousandweight ** 1200 lb 544.31 kg (if based on 16oz pound)
thousandweight ** 1200 lb 612.35 kg (if based on 18oz pound)
short ton 2000 lb 907.18 kg
ton (long ton) 2240 lb 1016.05 kg Ton generally used: 20 cwt (hundredweights)
tonne 1000 kg 1000 kg

** The heavier standard which here has been termed refining weight was used on Dartmoor to allow for losses in final refining and a tax levied onthat refining. In other words, it was a bit of a fiddle. The  thousandweight used in some records sometimes refers to the standard pound and sometimes to he heaver pound. Judgments have to be made which is in use in the document under consideration. Assumptions (guesses) often have to be made.

Troy Weight

Unit Dimension Metric Comment
Grain 0.0648 g equivalent in all three imperial tables of weight
Carat 3.086 grains 0.02 g
Pennyweight 24 grains 1.5552 g
Ounce 20 pennyweights or 480 grains 31.1035 g
Pound 12 ounces 373.24 g

Apothecaries’ Weight

Unit Dimension Metric Comment
Grain 0.0648 g equivalent in all three imperial tables of weight
Scruple 20 grains 1.296 g
Dram 3 scruples 3.888 g
Ounce 8 drams or 480 grains 31.1035 g
Pound 12 oz or 5760 grains 373.24 g

Brewers and Vintners Measures

Unit Dimension Metric Comment
Unit Dimension Metric Comment
bottle 0.75 litre EC Standardised Measure – a wine bottle was sometimes 0.70 litre, spirit bottles still are
magnum 2 bottles 1.5 litre Champagne measure, sometimes wine
methuslah 8 bottles 6 litre Champagne measure, sometimes wine
noggin about 1/4 pint approximate unit of capacity, also called gill
yard of ale 3-2 pints named after the glass – once you start you have to go on!
wine gallon 231 cu in 3.7854 litre archaic unit of capacity
anker 10 wine gallons 37.854 litre or 8.33 imperial gallons. Measure of wine of spirits. Unit of capacity found in Holland, North Germany, Russia, Denmark and Sweden. The Rotterdam measure is given here, which was also used in Britain. Also spelt ankor or anchor.
firkin 9 gallons 40.104 litre Also a wooden barrel of the same capacity
kilderkin ~ 18 gallons ~ 80 litre Origin possibly medieval Dutch
barrel 36 gallons 160.416 litre Brewing measure, 4 firkins.
hogshead 52½ gallons 233.94 litre Wine measure.
hogshead 54 gallons 240.624 litre Beer measure, 6 firkins.

Degrees Proof

Alcohol % by Volume Degrees Proof UK Degrees Proof US Comment
2 3.5 4
4 7 8 Beer Strength
6 10.5 12 Cider strength
8 14 16 Premium Beer and Extra Strong Cider strength
10 17.5 20
12 21 24 Wine strength
20 35 40
22 38.5 44 Sherry Strength
30 52.5 60
40 70 80 Whisky Strength
50 87.5 100
57.143 100 114.286
60 105 120
70 122.5 140
80 140 160


  1. […] Ancient and non-metric measures […]

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