measuring chain length the first time

[User]

 

[mjr]

Measure the chain stays and use one of the online calculators?

 

[Sharky]

Not sure if I've understood your situation? Just need to fit the sprocket and chain rings you want to use, wrap the chain round and cut it where it meets. If you cut it too short, just add two links back?
Good luck
Keith

 

[MichaelW2]

Parktools repair help has 3 methods.

 

[potsy]

Do what you did last time but instead of cutting it there leave it a few links longer