Latch hook rug making. How much yarn do I need?

[ampere]

Anyone know the coverage one pack of precut yarn gives? ie how many strands are in each pack?

I guess one can work out the amount needed if you count the holes in a rug canvas AND you know how many strands are in a standard pack!

Thanks anyone!

about 160 in the packs i get!

here

this is where i get mine, on the canvas i ordered from there there is a grid which marks off 100 in each box iyswim.