How this calculator works
The calculator finds wall area from length times height, subtracts openings, then divides by one block face area. It applies a waste percentage and rounds up to whole blocks. Courses are estimated from wall height divided by block height, and mortar bags use a rough planning rate.
Example: a 30 ft by 8 ft wall has 240 square feet before openings. After 40 square feet of openings, it has 200 square feet. With 16 in by 8 in blocks and 5% waste, the estimate rounds to 237 blocks.