Two cubits were used at this time, the old cubit and the royal cubit. The Bible probably refers here to the royal cubit, measuring 52.5 centimeters. The old cubit is 45 centimeters. See R. B. Y. Scott “Weights and Measures of the Bible,” Biblical Archeologist, Vol. 22 (1959), pp. 22–40, especially pp. 23–27; Gaby Barkay, “Measurements in the Bible—Evidence at St. Étienne for the Length of the Cubit and the Reed,” BAR 12:02.