Making sure braided/sleeved replacement cables are the correct length- any tricks?

[SFF EOL]

Is there a special trick for measuring the length of cables you need? I guess with some of the cases it is word of mouth, learning from other’s mistakes? But what about if your case isn’t that popular, and obviously everyone is using different internals. How do people go about getting just the right length?

In so far as I’ve done anything, I’m OK shortening most existing cables, but that is just me carefully shortening the existing cables- not sleeved. I’m tempted by the cables from Ali Express. I’ve never used Ali Express and I’m not sure how I would measure the lengths needed.

So, what/how do people do it? One way I have tried to do it is by actually using a length of cable and routing it then adding on for the connectors, but that would be a bit wasteful of cable. If I am going to then make that cable with connectors then it is ideal, but not if I just end up with lots of lengths of cable that I will not find a use for.

 

[Alexnader]

I was actually thinking about doing just this a few days ago, and the best I could come up with (don't judge if it sounds stupid) was to use a piece of string/twine.

Just place it from where the cable starts, to where you want it to end. Route it through the case, then when you're done just unfurl it and measure.

 

[tinyitx]

I was actually thinking about doing just this a few days ago, and the best I could come up with (don't judge if it sounds stupid) was to use a piece of string/twine.

Just place it from where the cable starts, to where you want it to end. Route it through the case, then when you're done just unfurl it and measure.

This is the way I did in the past.
Instead of using a string (which can be too 'flexible'), an improvement is to use an actual electrical wire, which should not be too hard to find a suitable length to do a measurement.
One can also use the cables supplied with the PSU. These cables are, usually but not always, too long. So, using those as a base estimate and then subtract the excess.

When ordering custom cables, the length can be specified with or without the height of the connector on both ends. I think, excluding the connectors is more often used. But, it is better to confirm with the seller which method is used.

Lastly, if one can end up with the exact length, then it is, of course, ideal. But often, it is good to err on the safe side. Ending up with slightly longer than needed cables is much better than having cables with just short of the needed length.