These are the 7mm beads. They are just under 1/4" wide. So figure 3 to 4 beads per inch.
35 beads will make a ten inch strand

The 10mm beads are just over 1/4" inch So figure about 3 beads per inch.
29 beads will make a ten inch strand.

The 12mm beads are just under 1/2" inch So figure about two beads per inch.
22 beads will make a ten inch strand

The 15mm beads are just over 1/2" 13 beads will make a 8" bracelet.