Pre-Decimal to Decimal Converter
Convert between pre-1971 British £sd (pounds / shillings / pence) and decimal pounds. Pure arithmetic — no exchange rate lookup or data feed required, so the converter never ages.
All decimal equivalents below are exact; the £sd system used base-12 (pence) and base-20 (shillings).
| Pre-decimal | Equals | Decimal pounds |
|---|---|---|
| 1 pound (£) | 20 shillings (s) = 240 pence (d) | £1.0000 |
| 1 shilling (s) | 12 pence (d) | £0.0500 |
| 1 penny (d) | — | £0.004167 |
| 1 farthing | ¼ penny | £0.001042 |
| 1 halfpenny | ½ penny | £0.002083 |
| 1 sixpence | 6 pence (d) | £0.0250 |
| 1 half crown | 2s 6d | £0.1250 |
| 1 crown | 5 shillings | £0.2500 |
| 1 sovereign | 20 shillings | £1.0000 |
| 1 guinea | 21 shillings | £1.0500 |
On 15 February 1971, Britain converted to decimal currency. 240 pence per pound (pre-decimal, "old pence") was replaced by 100 new pence per pound. The Royal Mint redesigned all denominations except those that aligned cleanly to a decimal value: the shilling continued as 5p, the florin as 10p, the half crown was withdrawn, and farthings, halfpennies, pre-decimal pennies were demonetised.
Looking to value a specific pre-decimal coin? Browse our British coin catalogue or read the florin, shilling, threepence, farthing and crown guides.