Construction Calculator - Concrete and Masonry

Concrete Calculator

Estimate concrete yards, bags, and slab cost from length, width, and thickness.

Reviewed: August 26, 2026

Calculate Concrete

For the Concrete Calculator, enter length, width, thickness, waste allowance, and ready-mix price. It returns allowance-adjusted cubic yards, 60- and 80-pound bag equivalents, and optional ready-mix cost for one rectangular placement.

Construction measuring tools arranged beside a residential building project

Formula used

Cubic yards = [length × width × (thickness ÷ 12) ÷ 27] × (1 + waste ÷ 100)

For a Pakistan house estimate that needs regional cement, sand, crush, and rate assumptions, compare the same measured scope with Grey Structure Calculator's concrete and cement planning tool. Keep the area, thickness, and quote date aligned before comparing totals.

Concrete Calculator measurement plan showing Length feet, Width feet, Thickness inches

Worked concrete example

Concrete Calculator example: 26.9 ft × 13.5 ft × 4 in ÷ 12 ÷ 27 × 1.1 = 4.93 yd³. The same volume is about 225 80-lb premixed-concrete bags or 296 60-lb bags using the calculator's bag-yield constants.

From calculated volume to an order

Use cubic yards when requesting ready-mix. Whole-bag counts are more useful for a small hand-mixed pad or repair than for a truck placement.

Where a concrete takeoff can drift

Uneven subgrade, form movement, pump priming, spillage, and the ready-mix producer's batch and delivery rules can change the practical order.

Questions specific to this calculation

Which finished dimensions define the concrete placement?

Measure each rectangular placement separately and use the formed dimensions, including any thickened strip that will be poured with the main section.