In 1883, the dimensions of the football were given in imperial measurements :
the circumference had to be between 27 and 28 inches, and the mass had to be between 16 and 18 ounces.

It wasn't until 1935 that the current specifications were introduced :
the circumference didn't change, but the mass now had to be between 14 and 16 ounces.

1 inch (pouce) = 2.54 cm and 1 ounce (once) = 28.35 g

In 1883, the mass of a football had to be between and .

Since 1935, the mass has had to be between and

Since 1883, the circumference of a football has had to be between and round to the nearest cm