Two calculators live in the More tab, for the two sums that come up over and over.
Skein Calculator
“The pattern wants 1,200 metres and my yarn is 175 metres a ball — how many do I buy?”
Enter the length per skein from the ball band and the total the pattern requires, and it tells you how many skeins that is. There’s a Yards / Meters switch, so you can work in whichever unit the two numbers happen to be printed in.
It rounds up, because two-thirds of a ball isn’t something a shop sells you.
Buy one more than it says if the colour matters. Dye lots vary, and coming back for the last ball six months later rarely ends well — see Yarn groups for keeping track of which lot you have.
Yarn Weight Converter
“The pattern says Aran. What’s that in the shop I’m standing in?”
Pick a weight system and a yarn weight, and it shows the Equivalents across the others — so DK, 8-ply, light worsted and the rest line up. It also lists the Specifications: the gauge range and the hook and needle sizes usually used with it.
Handy when a pattern is written in one country’s vocabulary and your yarn was bought in another’s.
Which unit things appear in
Both tools respect the length unit you prefer, and lengths elsewhere in the app can be tapped to switch — see Yards or metres?.