Originally Posted by FBinNY

I've said this so often it's like a Mantra.

There are 3 chain lengths.

1- the Minimum - found by the big/big +1" method (note: this is an absolute minimum method with no fudge room.
2- the Maximum - found by the small/small & take up slack method. This has some fudge room if wide range gearing exceeds RD take up capacity.
3- Correct length - anything between the minimum and maximum, according to RD cage orientation, or your preference.

I run chains near the maximum because it leaves me room to change to a larger cassette or remove damaged links if I ever need to. While some people run minimum length and carry spare links, my spares are already in the chain.

IMPORTANT -- the minimum is an absolute non-fudgeable length, so unless you're sure your gear combination is within RD capacity, measure the minimum and confirm that your length is longer. Or if confident, shift into big/big (slowly) after cutting to confirm.