The Trial of the Pyx is a judicial ceremony in the United Kingdom to ensure that newly minted coins from the Royal Mint conform to their required dimensional and fineness specifications. Although coin quality is now tested throughout the year under laboratory conditions, the event has become an annual historic tradition. Each year, thousands of coins are put on trial, consisting of both those struck for circulation and non-circulating commemorative coins.

The standard circulating coinage of the United Kingdom, British Crown Dependencies and British Overseas Territories is denominated in pennies and pounds sterling, and ranges in value from one penny sterling to two pounds. Since decimalisation, on 15 February 1971, the pound has been divided into 100 (new) pence. Before decimalisation, twelve pence made a shilling, and twenty shillings made a pound.