John Calvert (1726–1804), was an English brewer and politician who sat in the House of Commons for 48 years between 1754 and 1802. Calvert was born on 6 May 1726 the son of Felix Calvert of Albury Hall and his wife Mary Calvert daughter of Felix Calvert of Nine Ashes, Hertfordshire who was his second cousin. The Calvert family were London brewers who owned the Peacock Brewhouse in Whitecross Street and the Hour Glass brewhouse in Thames Street.