Use our conversion tool to go from inches to centimetres.
To convert a circumference to a diameter use the following formula.
If you know the circumference (of the dildo, for example), divide it by 3.14 to get the diameter.
For example, if the circumference of the dildo is 10 cm, the diameter is 10 cm divided by 3.14, being 3.18 cm.
Use the calculator below if necessary.