Calculator collection
Slabs & flatwork calculators
Calculators for slabs, pads, patios, driveways and round pours.
Concrete Calculator (Metric, m³)Free metric concrete calculator. Enter metres and centimetres for slabs, footings, columns, walls or steps to get cubic metres, kg and bags.Open calculator Concrete Curb CalculatorFree concrete curb calculator. Enter length and curb and gutter dimensions to get cubic yards per linear foot, ready-mix order, bags and weight.Open calculator Concrete Curing TimeConcrete curing time: keep new concrete moist 5–7 days, protect it from freezing for 48 hours and expect full rated strength at 28 days.Open calculator Concrete Cylinder CalculatorFree concrete cylinder calculator for round pads and hollow cylinders (pipe, ring, tank wall). Enter diameters and height for yd³, m³, weight and bags.Open calculator 
Concrete Driveway CalculatorFree concrete driveway calculator. Enter length, width and thickness to get cubic yards, m³, 40–90 lb bag counts and an order amount for any driveway.Open calculator Concrete Patio CalculatorFree concrete patio calculator. Enter size and thickness to get cubic yards, ready-mix order and 80 or 60 lb bags for square, L-shaped or round patios.Open calculator Concrete Sidewalk CalculatorFree concrete sidewalk calculator. Enter walk length, width and thickness to get cubic yards, ready-mix order and 80 or 60 lb bags for any walkway or path.Open calculator 
Concrete Slab CalculatorFree concrete slab calculator. Enter length, width and thickness to get cubic yards, 40–90 lb bag counts, weight and cost for any slab, pad or floor.Open calculator Concrete Slab Thickness CalculatorFree concrete slab thickness calculator. Enter slab size and the yards or bags you have to get the average thickness, plus concrete needed at 4, 5 and 6 in.Open calculator 
Self-Leveling Concrete CalculatorFree self-leveling concrete calculator. Enter floor area and thickness to get the volume and number of bags of self-leveling underlayment to buy.Open calculator Types of Concrete FinishesTypes of concrete finishes compared: broom, float, trowel, stamped, exposed aggregate and colored, with when to apply each and where each works best.Open calculator FAQ
Frequently asked questions
How do I calculate concrete for a slab?
Multiply length × width in feet by thickness in feet to get cubic feet, then divide by 27 for cubic yards. A 10 × 10 ft slab 4 in thick is 10 × 10 × 0.333 = 33.3 ft³, or 1.23 yd³. Add a waste allowance before ordering; the slab calculator does both steps.
How many square feet does a yard of concrete cover?
One cubic yard covers 324 ft² at 1 in thick, so divide 324 by the thickness in inches: 81 ft² at 4 in, 65 ft² at 5 in and 54 ft² at 6 in.
How much extra concrete should I order?
NRMCA's guide to ordering ready-mixed concrete suggests ordering 4–10% extra to cover uneven subgrade, form flex and spillage. Our calculators include a waste field so you can set this yourself.
Which calculator should I use for a driveway or patio?
Use the driveway calculator for drives and the slab calculator for patios and pads. Both give cubic yards, bag counts and weight; the maths is the same, only the default thickness differs.
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