John Gill Bible Commentary

And the shekel shall be twenty gerahs,.... This is a rule for money or coin; the shekel was a silver coin, and is generally reckoned about the value of two shillings and six pence of our money, so a gerah about three half pennies: Bishop Cumberland reckons the shekel more exactly at two shillings and four pence farthing, and a little more, and the gerah at eleven grains of silver; see Lev 27:25, twenty shekels, five and twenty shekels, fifteen shekels, shall be your maneh; these were several pieces of money; one was a twenty shekel piece, which according to the common account was fifty shillings of our money; another was a five and twenty shekel piece, which was three pounds, two shillings, and sixpence; and a third was a fifteen shekel piece, which was one pound thirteen and sixpence; and together made a maneh or pound, which consisted of sixty shekels, or seven pounds, ten shillings; by which the other pieces should be tried, whether they were of just weight: the sense of the whole is, that no adulteration of coin should be made, which is very prejudicial in civil affairs.