Pipe Size Calculator

Select a pipe bore.
Select a type of size (Face to Center, Center to Center, etc).
If the size uses a tee an option will show to select a branch size.
Input the length of size (numbers only) required in millimetres.
Hit the flashing calculate button.
You will see a size of pipe to cut.
Cut, thread and make on your fittings.
As long as you've made the correct thread length, your size is now complete.