Weaving Calculations for Balanced Weave
To decide how long you need to make your warp, figure out the total finished length of your warp and add about 20-24" for loom waste and take-up. To figure out how many yards you need for the warp, multiply the ends per inch (epi) by the length of warp.
If it's a balanced weave (warp and weft are using the same yarn weight), we typically figure you need the same amount for the weft as you do for the warp. It's really more like 80-85%, but better to have too much yarn than too little.
For the example here, let's assume that we're going to use a worsted weight yarn with an 8 dent reed and make a scarf that's 7 inches wide and 70 inches long.
1. Number of ends per inch (epi): 8
2. Width of project in inches: 7
Multiply 1 and 2 to get the number of warp threads (A): 56
3. Length of project in inches plus 20-24" loom waste and fringe (B): 90
Multiply A x B 5,040 then divide by 36 140
Yardage for warp: 140 yards
Yardage for weft is same: 140 yards
Total yardage for project: 280 yards