Formula and limits
Walls = 2 × (length + width) × height. Optional floor = length × width. Opening blocks are deducted only when they do not exceed the shell. Roofs, decoration, wall thickness, costs, and game rules are not included.
Lucky Block World Build Material Estimator
Interactive length, width, height, openings and floor inputs give a wall, floor and total breakdown with visible exclusions. This working estimator shows wall, floor, deduction, footprint, perimeter and final block outputs plus visible rectangular-shell assumptions.
Estimate a simple room shell
One-block-thick walls and an optional floor. Roofs, decorations, costs, and game limits are not included.