Brick Quantity Calculator

Neither dominates -- they have an identical, proportional effect on Total Bricks Needed, because both feed directly into Net Wall Area (Wall Length x Wall Height minus Openings) the same way. At the default 20x8 ft wall, increasing either dimension to 110% of its value raises the brick count from 1,102 to 1,211 bricks -- the same result regardless of which dimension changed.

Bricks Per Sq Ft equals 144 divided by the brick's footprint including its mortar joint, so a larger Brick Length or Brick Height lowers the bricks-per-square-foot rate and reduces Total Bricks Needed; growing Brick Length from 8 to 8.8 inches drops Bricks Per Sq Ft from 6.6 to about 6, meaning fewer, larger bricks cover the same wall.

Waste Factor adds a percentage on top of the base brick count computed from wall area and brick size, to cover cuts, breakage, and pattern waste. It's a small but direct multiplier -- raising it from the default 5% toward 10% for complex patterns increases Total Bricks Needed proportionally without changing Bricks Per Sq Ft. It does, however, move Mortar Volume and Mortar Bags, since both are computed from Total Bricks Needed: raising Waste Factor from 5% to 10% moves Mortar Volume from 7.71 to 8.08 cu ft and Mortar Bags from 16 to 17 at the default wall size, because more bricks means more mortar joints to fill.

Yes, indirectly: Mortar Joint Width is added to both Brick Length and Brick Height before Bricks Per Sq Ft is computed, so a wider joint slightly reduces the number of bricks needed per square foot (a bigger effective module), while also increasing Mortar Volume and Mortar Bags in the same calculation.