For a 9 Patch style block, which this one is, it is easier to keep your measurements divisible by 3. A 10 inch block is doable but it makes your math all weird. Each square would need to be trimmed down to 3.84" I don't have a .84 mark on my ruler--LOL! For the least amount of waste, I would use the figures I gave earlier for a 5" charm which will result in a 12" finished (12.5" unfinished) block.