Dora Stuart Primrose Metcalf (11 March 1892 – 17 October 1982) was an India-born Irish entrepreneur, mathematician and computing pioneer.

During World War II she was involved with supplying the "bombe" decryption machines to the codebreakers at Bletchley Park in England.

[2] During World War I she worked as a comptometer operator in a munitions factory during which time she came to realise the potential of the mechanical calculator as a descendant of the abacus.

After her fiancé Lt. Hugh Launcelot Cass (1891–1915) was killed by a sniper at Cape Helles in Turkey during the Gallipoli campaign during World War I she thought of herself as one of the 'surplus women' and gave up hope of ever marrying due to the loss of so many men's lives[1] and concentrated on a career in computing, from 1916 selling comptometers in Belfast in Ireland.

[2] During World War II BTM supplied the "bombe" decryption machines to the codebreakers at Bletchley Park in England.

After the War in 1949 Metcalf worked with physician Dorothy Price on the BCG tuberculosis vaccination programme in Ireland through St Ultan's Hospital.

[4] John and Dora Metcalf enjoyed fishing for salmon and trout and in order to pursue this hobby on their retirement they relocated from London to Loch Morar, where they stayed until 1970 following which they spent their final years in Otley in Yorkshire.