Sometimes called a chalder. When used for coal the chaldron was in some times and places a unit of mass and in others a unit of capacity.


In England, 15ᵗʰ – 19ᵗʰ century, a unit of dry capacity used for grain, = 4 quarters = 32 bushels.


In England, 15ᵗʰ – 19ᵗʰ century, a unit of dry capacity used for coal. See keel.

The custom's Book of Rates of 1660 speaks of three chalders:

Sea Coles the Chalder New Castle measure exported by English in English built Bottomes
Sea Coles the Chalder London measure exported by English in English built Bottoms
Sea Coles of Wales or the West countrey which shall be transported into Ireland the Isle of Mann or Scotland to pay xij d. the Chalder water measure

The distinction between the London and Newcastle chaldron appears at least as early as 1580. Hayes (1740, page 206) states that “8 Chaldron at Newcastle makes at London about 15 Chaldrons.”

Coal was taxed by the chaldron, not by weight, so it was to the seller's advantage to make the chaldron as large as possible.

The Newcastle chaldron

The Newcastle chaldron, used only for coal. Before 1695 its weight was taken to be 42 hundredweight (about 2134 kg). In 1695 it was standardized at = 72 heaped bushels¹.  One chaldron was enough to fill three wains (wagons), in which case it was reckoned as 52½ hundredweights (5880 pounds, about 2667 kilograms).

1. 6 & 7 William III chapter 10 1695.

Simmonds (1892), page 81.

The London chaldron

By a law of 1665, 1 chaldron = 36 bushels, weighing 25 1/3 hundredweights, about 2837 pounds avoirdupois (about 1287 kilograms).

All sorts of coale commonly called sea-coals brought into the River Thames and sold, shall be sold by the chaldron containing thirty-six bushels heaped up according to the bushel sealed for that purpose in the Guildhall.

16 & 17 Charles II chapter 2, 1664-1665.

The water measure chaldron

On shipboard 1 score of chaldrons was not 20, but 21 chaldrons.

At Newcastle, if the coal was loaded on shipboard the chaldron was reckoned at 53 hundredweights (5936 pounds, about 2692.5 kilograms).

The Weights and Measures Act of 1835² required all coal to be sold by weight, not by measure, an injunction repeated in the Weights and Measures Act of 1878³, which nonetheless again defined the chaldron at 36 bushels.

The chaldron was abolished by the Weights and Measures Act of 1963.⁴

2. 5 & 6 William IV chapter 63 sec 9. A Collection of the Public General Statutes, passed in the Fifth and Sixth Year of the Reign of His Majesty King William the Fourth. London: Eyre and Spottiswoode, 1835. Page 288.

3. 41 & 42 Victoria chapter 49 section 6, 1878. Public General Statutes Volume 13, pages 308-341.

4. Elizabeth II chapter 31 1963. London: Her Majesty's Stationery Office, 1964.



While the size of the keel now remained stationary, the size of the chaldron (on which the duty was paid) began to grow; and with such success was this policy pursued during a prolonged period, that when it was finally put a stop to, some two hundred and fifty years later, the chaldron had attained to two and a half times its original size, and the carefully marked keels were only carrying eight instead of the original twenty chaldrons. At the same time it seems not improbable that this continual increase in the size of the chaldron may have been owing to the temptation to give extra measure in order to secure trade, rather than with the direct object of evading the royal duty.

pages 68-69


The chalderne of sea cooles is 12 sackes of sea coole, euery sacke ought to conteyne 4 bushells watter measurs, the bushel hepid as much as yt will stand, so that the chalderne is 48 bushells in grosse.  With euery 20 chalderne theris one chalderne alowance to the byer.

Geometry upon Waights and Measures calid the Art Statike.
MS Reg. 18 C. XX 1590-1620.
From Hall and Nicholas, 1929, page 24.


Coals are sold and shipped at Newcastle, Sunderland and Blyth, by the chaldron, weighing fifty three hundred weight. it is impossible to ascertain with precision the number of chaldrons, of thirty-six bushels, which each cargo, when delivered, ought to make out, owing to the specific gravity of the coals, and to there being a greater or less quantity of large or small coal in the cargo; but it has been stated to us by the officers of the customs at Newcastle, that eight Newcastle chaldrons, when delivered in the port of London; have, till within the last twelve months, made out nearly double, and since that time about fifteen London chaldrons; and that the same quantity, when delivered in most of the out-ports, makes out about sixteen chaldrons, and sometimes more.

The deliveries in the dock yards should bear the same proportion to the Newcastle chaldrons as those made on the river Thames, as they are alike measured by the vat; for although there is an allowance to the buyer in the port of London of one chaldron upon twenty, called ingrain, yet the duty is paid upon the actual quantity delivered including that allowance.

Robert Edington.
A Treatise on the Coal Trade with Strictures on its Abuses and Hints for Amelioration.
London: 1813.
Page 249.


In Atlantic ports during the age of coal-fired steamships the chaldron of coal had various magnitudes. Picton, Nova Scotia, 3456 pounds; New York City, 2500 pounds; United States generally, 2940 pounds.

Simmonds (1892), page 81.


A unit, probably of mass, used at least in customs for stones used to line drainage ditches. We do not know its magnitude or whether it is equivalent to one of the chaldrons for coal.

Grindle stones the chaldron

“A Subsidy granted to the King of Tonnage and Poundage and other summes of Money payable upon Merchandize Exported and Imported.”
A statute from the 12th year of Charles II, 1660. The selection is from the Booke of Rates, which is not part of the statute proper but developed from it. Both are printed in:
Statutes of the Realm, Volume 5: 1628-80, John Raithby, editor.
London: 1819.

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