Calculating skirting board/coving

[Itsallpointless]

As the title says, how do I do it? Looked on google but still don't understand. Is there anyone who can help a novice DIYer please

Yeah - let your builder do it lol

Add all your wall lengths together is the short answer then add 10%

Surely perimeter of the rooms + a few extra lengths for contingency

Wish I could afford a builder @Loofah01

Thanks for your help

Agree lengths plus 10% and usually the pack size makes the decision for you on how much to round up.
You'll always cut a couple the wrong way on the 45 degree, especially coving which has 4 different ways to cut it at 45 degrees, 3 of them are wrong! Whereas skirting only has one wrong and one right. There's always a bit of wastage on the internal corners too as it pokes out further into the room than the short way round the corner, if that makes sense. It has to take the wide route around the corner

Also, you'll and up with a few short offcuts and you'll want to use full lengths where possible, otherwise you'll end up having a bit at the end where you're trying to line up all the silly left over bit.

@johnd2 I have a mitre block for the coving, will this help me cut it the right way? I'm assuming everyone uses one of these?

I would take account of the lengths it comes in to minimise cuts.

Mitre block will help you get the angle right, but you have to put the coving in the block the right way as well.
And as you can imagine suppose you have a Mars bar and that's your coving, you could put it either "mars" or upside down "sram"facing upwards in the block. And then you could also put it with the "mars"or"sram" facing the front, and that would be different.
(Facing down or backwards would be duplicates of the previous, so there are 8 ways but only 4 cuts would result.)

@johnd2 oh my, maybe I should do my measurements plus 50%

You can always get extra, and in normal circumstances I'd say return the excess when you've finished the project, but I'm not sure how returns work at the moment.