Three eighths of an inch is roughly 9.5 millimetres. This is just short of one centimetre.

To see for yourself how large this is, you need to find yourself a ruler or tape measure. If you do not own a ruler or tape measure, these can be purchased at most do it yourself stores or a stationery store if you want a basic ruler.

On most rulers, there are centimetres on one side of it and inches on the other, but this can vary. The best way to check before you buy is to have a quick look on the very end of each side; this should tell you whether the ruler is centimetres (cm) and inches (inch). Sometimes it will also say millimetres (mm), which are a smaller measurement within centimetres.

Rulers usually measure in both metric length, which is the newer measurement, which is centimetres, and imperial, the older measurement, inches. You should be able to easily compare the three eighths of an inch you require to the 9.5 millimetres that it is equal to.

It is useful to be able to convert imperial into metric because a lot of measurements are now taken in metric rather than imperial.

To see for yourself how large this is, you need to find yourself a ruler or tape measure. If you do not own a ruler or tape measure, these can be purchased at most do it yourself stores or a stationery store if you want a basic ruler.

On most rulers, there are centimetres on one side of it and inches on the other, but this can vary. The best way to check before you buy is to have a quick look on the very end of each side; this should tell you whether the ruler is centimetres (cm) and inches (inch). Sometimes it will also say millimetres (mm), which are a smaller measurement within centimetres.

Rulers usually measure in both metric length, which is the newer measurement, which is centimetres, and imperial, the older measurement, inches. You should be able to easily compare the three eighths of an inch you require to the 9.5 millimetres that it is equal to.

It is useful to be able to convert imperial into metric because a lot of measurements are now taken in metric rather than imperial.