Concrete Calculator: Bags, Mix

A construction calculator with a cement calculator, rebar calculator, brick calculator and mortar calculator built in. Use it as a slab calculator, cubic yard calculator and volume calculator for concrete, plus a rebar weight calculator and tile calculator.

Pick a shape and get your concrete volume in seconds. Work out the cubic yards (or m³) and premix bags you need for slabs, footings, columns and steps — then estimate mix, blocks, rebar, plaster and tile in the same app.

■ Concrete volume with visual guides
• Every shape comes with a dimension diagram. Just fill in the a · b · c lengths shown in the picture.
• Shapes: slab / wall, footing (ring, 2-cell, 3-cell, 4-cell), column (square, round, hollow tube), steps, cone footing (bell / tapered pier) and trapezoid (retaining wall, ditch)
• Quantity and waste allowance (0, 5, 10, 15%) built into the total
• Premix bag count: 40, 60, 80 lb / 20, 25, 40 kg
• Enter a price per cubic yard (or m³) to estimate cost

■ Enter dimensions exactly as drawn
• Choose the unit for each field: ft, in or yd (metric: m, cm, mm)
• Length in feet, thickness in inches — no conversions needed
• Your unit choice is remembered for every field

■ Concrete mix
• Send the calculated volume to the mix calculator with one tap
• Mix ratios 1:1.5:3 (strong), 1:2:4 (general), 1:3:6 (lean)
• Cement, sand and gravel (lb, ft³), water (gal) and cement bags (47 / 94 lb)

■ Blocks & bricks
• Standard CMU (16 × 8) and brick sizes built in, or enter your own
• Mortar joint included, door and window openings subtracted
• Units needed and cost with waste and unit price

■ Rebar weight
• ASTM bar sizes #3 to #10 (metric: KS D10–D32)
• Total weight and total length from bar length and count, plus cost by price per lb

■ Plaster
• Cement bags and sand from wall area, plaster thickness and mix ratio (1:3 to 1:6)

■ Tiles
• Enter room dimensions or total area
• Tile count with tile size and grout gap
• Price per tile, per area or per box — add tiles per box to get the number of boxes

■ Save and share
• Save results with a job name and reopen them later with every input restored
• Share results by text or messenger in one tap

■ Built for
• Contractors and foremen checking yardage before ordering ready-mix
• Small builders and remodelers preparing estimates
• DIYers pouring a patio, driveway, fence footing or steps

■ Also
• Imperial (ft · in · yd) and metric (m · cm · mm) units
• Free to use, with an optional one-time purchase to remove ads

Note: Results are estimates. Check site conditions, product specs and your supplier before ordering. Use a designed mix for structural concrete.