The British decimal halfpenny (1⁄2p) coin was a denomination of sterling coinage introduced in February 1971, at the time of decimalisation, and was worth 1⁄200 of one pound.

The possibility of setting prices including an odd half penny also made it more practical to retain the pre-decimal sixpence in circulation (with a value of ⁠2+1/2⁠ new pence) alongside the new decimal coinage.

[1] The UK Treasury argued the halfpenny was important in the fight against inflation, as it prevented prices from being rounded up.

The half penny coin was legal tender for amounts not exceeding 20 pence.

A decimal quarter-penny coin (to be struck in aluminium) was also proposed (which would have allowed the pre-decimal threepence to continue to circulate with a value of 1+1⁄4 new pence), but was never produced.