Patrick Kelly (1756–1842) was a British metrologist, best known for his comparative studies of weights and measures collected in his works Universal Cambist (1811) and Oriental Metrology (1832).
[1][2] Kelly was Master of the Finsbury Square Academy, London.
[4] Kelly knew Nevil Maskelyne, John Herschel, James Hutton, and other men of science.
He was consulted by committees of the House of Commons as an authority on questions of coinage and currency.
A portrait of him by Harry Ashby was engraved by Thomas Woolnoth.