Blinking snake

The British Monetary System before Decimalization

Constellation band

The Mad Hatter G. Vinton Palazzolo asked a question on the Calendar Mailing List about the practicality of the mixed-radix calendar calculation system of the Classic Maya. I responded by saying, “Don’t forget the British Monetary System before decimalization, which is the classic example of a complex mixed-radix counting system in constant, daily use for hundreds of years.” Naturally, she asked me to explain this monetary system, and when it was decimalized. Since I use this as an example all the time, I thought I had better do some research, find out, and write it up. I wish to acknowledge the assistance of Alan McLaren, who grew up in Australia before the switch to dollars, and was able to fill in some gaps for me. Also, thanks to Jeremy Smith, who so kindly allowed me to use parts of his dictionary


The following excerpts from the British->American Dictionary page are used with the permission of Jeremy Smith,

£ (a Latin L):
pound, symbol for pounds sterling. 1971 was the year of decimalization of the British currency when a pound became 100 new pennies. Prior to that a pound was 20 shillings, a shilling twelve pence (pennies) and the smallest division of a penny was a farthing. It is written £/s/d and £/s/- for even shillings. From 1776 till WWII £1 fluctuated between $3-$5 (1864 peak of $12). Since WWII it has fluctuated around $2 when 1d was 1¢ (low of $1.04 in 1985). Hence, the slang ‘dollar’ for 5/- and ‘half a dollar’ was accurate until the early 70s.
£sd /el es dee/ n:
‘pounds, shillings, and pence’, money in general, and the British monetary system in particular prior to decimalization (4 farthings = 1 penny, 12 pence = 1 shilling, 2 shillings = 1 florin, 5 shillings = 1 crown, 20 shillings = 1 pound (sovereign), 21 shillings = 1 guinea).
¼d /fahdhing/:
symbol for a farthing, four to a penny, about the size of a copper cent, went out of circulation in 1956.
½d /haypnee/:
symbol for a halfpenny, about the size of a thin copper quarter.
1d /penee/ n:
symbol for penny.
2d /tuhp@ns/ n:
twopence, (also symbol for half groat).
3d /threp@ns/ /thr@p@ns/ /thruhp@ns/ /thrup@ns/ /fr@p@ns/:
symbol for threepence, threepenny bit, silver (about size of a dime) until 1920, then 12-sided brass coin like a fat nickel.
4d n:
symbol for groat.
6d /sicksp@ns/:
symbol for sixpence, about size of a dime, syn. tanner.
1/-, 1s, 12d:
symbol for shilling (12d), about size of a quarter, still in circulation, equivalent to 5p, syn. bob, shilling bit.
symbol for florin, two shillings, about the size of a half dollar, still in circulation, equivalent to 10p, syn. two bob.
2/6d /too n siks/:
symbol for half a crown, two-and-six (pence), larger than a half dollar.
symbol for crown, five shillings, huge, much larger than a silver dollar.
symbol for (brown) ten shilling note, syn. ten bob note.
ten-and-six, also half a guinea (see Mad Hatter’s topper).
20/-, £1, 240d, 100p:
alternate for £1 (green), pound, pound sterling, sovereign.
symbol for guinea, twenty-one shillings.
symbol for one pound note (green), first issued in 1928, new note issued in 1968, and reverting back to coins in 1983.
symbol for five pound note (blue, though, like the tenner’s, they used to be huge white sheets inscribed with gold filigree, large enough to wrap up plenty of money in).
symbol for ten pounds (brown) or ten pound note.
£20 n:
symbol for twenty pounds or the twenty pound note (rainbow colors).
bronze 1971-1985.
bronze 1971.
2p n:
bronze coin, about the same size as a Susan B. Anthony dollar.
5p n:
cupro-nickel coin, made exactly the same size, shape and value as the old shilling.
10p n:
coin introduced in 1982.
coin introduced in 1982.
seven sided coin introduced in 1969.
Long-necked Alice

ackers [Egyptian, akka, one piastre] n:
pound notes or money in general.
bent adj:
gay, “bent as a three-pound note”, “bent as a nine-bob note”.
bit n:
coin when used with its value, as: threepenny bit, sixpenny bit, two shilling bit, as opposed to note.
bob n:
shilling, “lend me a bob, mate”. (See a couple of bob, ten bob)
bun penny n:
a Queen Victoria penny bearing her portrait with her hair done up in a bun (1860-1874), and found occasionally in one’s change even up till decimalization.
couple of bob n:
some money, “I bet that set you back a couple of bob”.
crown n:
five shilling piece, 5/-, dollar.
decimalization n:
the changeover from £sd to decimal currency (100 new pence = £1), initiated in 1968 with introduction of 5p and 10p coins and completed by 1971 with the ½p, 1p, 2p, 20p and 50p, where 100p = £1.

The official start of the new currency was February 15th, 1971. The old currency stopped being used about 6 months later, although the changeover period was originally scheduled to last a year.

The 5p and 10p coins were the same size as the old 1/- and 2/- coins, and no attempt was made to withdraw these old coins from circulation, to the confusion of the visitor. However, in 1990 and 1992 new, smaller, coins for 5p and 10p were introduced, and the old ones withdrawn a year or so later. The only pre-decimalisation coins still being minted are the crowns (5/-) occasionally minted to mark special occasions.

dollar sl n:
five shilling piece, 5/-, five bob, 25p.
farthing n:
¼d, coin of least value, “haven’t got two brass farthings to rub together”.
fiver sl n:
five pound note, £5.
flim [flimsy] n:
five pound note, esp. from before the war (WWII).
florin n:
two shilling bit, 2/-.
groat n:
4d, silver coin 1351-1662, fourpenny bit 1836-1856, small sum, “don’t care a groat”.
guinea n:
gold coin last coined in 1813, but still used to refer to 21/- values.
half a crown n:
a value of 2/6d, or the half crown coin, about the size of a silver dollar.
half a dollar sl n:
half a crown, 2/6d, (12½p).
half-crown n:
another way of saying and writing half a crown.
halfpenny /haypnee/ /hayp@ns/ n:
ha’p’orth /hayp@th/ n:
halfpenny’s worth, but used in reference to any trifling amount, “he’s not worth a ha’p’orth”.
p /pee/ n:
symbol for new pence.
new pence n:
the new decimal currency (see decimalization) where 100 new pence equal a pound (100p = £1), as opposed to the old £sd currency. ‘New’ money has 1p /wun pee/, /nyoo penee/ or /penee/; 2p /too pee/ sometimes /tuhp@ns/: about the size of a large copper quarter; 5p: exactly the same size shape and value as the old shilling, about the size of a quarter; 10p: exactly the same size shape and value as the old two shilling piece, about the size of a half dollar; 20p: a small five sided brass coin about the size of a thin nickel; 50p: seven sided coin about the size of a silver dollar; and finally the sov=100p
nicker sl n:
pound (£), “it cost ’im twenty nicker”.
note n:
bill when used with value, as: ten shilling note, one pound note, five pound note; see bit.
old penny n:
the penny before decimalization.
quid n:
£1, one pound sterling, same as buck for dollar.
shilling n:
see 1/-.
sov col abbr:
sovereign n:
gold coin worth £1, now used to refer, with a hint of irony, to the new brass pound coin about the size of a squat fat quarter, there are five kinds differing by the inscription on the side and the design representing the four countries comprising the UK and the UK as a whole; pound notes were done away with in 1986.
sterling n:
British currency, syn pound, see £.
tanner sl n:
sixpenny bit, sixpence, “spare us a tanner, mate”.
ten bob n:
ten shillings or half a pound, but usually referring to the ten shilling note (until they went of circulation in 1971).
tenner sl n:
ten pound note.
topper n:
top hat.
twopence halfpenny /tupneeyaypnee/ csl n:
a trifling or worthless amount.
twopence /tuhp@ns/ n:
2d, two pennies, half groat.

The Mad Hatter sings while the Dormouse sleeps

Here are some tables for comparison.

British Money, The Simple Version

This is the standard mixed-radix system that was the basis of pre-decimal British currency, which had been in use since approximately 775 AD, and which went out of use, at least officially, in 1971. The table doesn’t attempt to include all possible bases; including a column for guineas, for example, would have meant using a base of 1.05—which makes my brain hurt a lot.

Position: 3 2 1 0
Name: Pound Shilling Penny Farthing
Value: 20 Shillings 12 Pence 4 Farthings 1 farthing
Radix: 103 202 121 40
Equivalents: 20 shillings,
240 pence,
960 farthings,

0.95238095 guinea,
1.9047619 half-guineas,
10 florins,
4 dollars,
4 crowns,
8 half-crowns,
8 half-dollars,
60 groats,
120 half-groats,
480 halfpennies,
120 twopence,
80 threepence,
40 sixpence
12 pence,
48 farthings,

0.047619048 guinea,
0.095238095 half-guinea,
3 groats,
6 half-groats,
24 halfpennies,
6 twopence,
4 threepence,
2 sixpence
4 farthings 1 farthing
Symbol: £
Pound coin
Shilling coin
Penny coin
Farthing coin

The Mayan Calendar

Position: 4 3 2 1 0
Name: Baktun Katun Tun Uinal Kin
Value: 20 Katuns 20 Tuns 18 Uinals 20 Kins 1 Kin
Radix: 204 203 202 181 200
Equivalents: 20 katuns,
400 tuns,
7200 uinals,
144000 kins
20 tuns,
360 uinals,
7200 kins
18 uinals,
360 days
20 kins 1 kin
Symbol: Baktun






You tell me which one is simpler ;-)!

In this style 10/6

Of course, after I posted my response, Lars Osterdahl, on the same mailing list, replied with this:
The British monetary system! Are we blind?
There is a much closer example:

Century   base 100
Year       "   100
Month      "    12
Date       "   28/29/30/31  ! a beauty !
Hour       "    24  (or the AM/PM system: 2 x 12)
Minute     "    60
Secs       "    60
(and below, decimal again)

I think the Guinness Book of Records has a clear winner here.


I guess I ought to build a table for that, too. ...

Previous Page
Table of Contents
Next Page

Main web site:

Valid HTML 4.01 Transitional