Is this what you are looking for? I found it in my files.
Half Square Triangles Directions
Here's the chart we were given, but I have not tested any of them to see if the final is with or without the 1/4" seam.
2" sq = 1 " HST
2.5 = 1.5
3.5=2
4=2.5
5=3.5
6=4
7=4.5
8=5
8.5=5.5
9=6
10=7
I believe the size you get is unfinished as I started using this method. Then I don't have to square them up if I am careful how I sew.
The chart which was displayed says a 7" block will = 4 4 1/2" hst, but I think I would cut in a half-inch bigger. You can always trim if it's too big.
When you cut these on the diagonal you will have two left over strips. Sew them together on the straight side and you can cut some more hst's