Concrete and masonry calculators
How many yards, how many bags, how many blocks? Slabs, posts, footings, steps, block and brick walls, mortar and stucco, worked out before you order.
What are you pouring or building?
Pick your project — each one opens its own calculator, then the next steps.
- Slab, patio or padCubic yards and bags of concrete for a slab, patio, pad or round slab, with waste and weight.
- Fence or mailbox postsBags of concrete per post hole for fence, gate, mailbox and chain-link posts, net of the post, gravel and any soil cap.
- Deck footings & tubesBags of concrete per Sonotube or cardboard tube form by diameter and depth, for one tube or a whole deck.
- Concrete stepsBags and cubic yards of concrete for solid poured steps, with or without a top landing.
- Block wallHow many concrete blocks (CMU, cinder blocks) for a wall, with courses, blocks per course, mortar bags and waste.
- Brick wall or veneerHow many bricks for a wall or veneer — modular, queen, king, Norman and more — with bricks per square foot and mortar.
- Fire pitHow many wall blocks, bricks or cinder blocks for a round or square fire pit, per course and in total.
- StuccoBags of base coat and finish coat stucco for a wall, for three-coat over lath or two- and three-coat on block.
Every calculator, by project
Slabs, yards & bags 3
Cost, weight & conversions 4
Footings, tubes & posts 3
Steps, walls & shapes 4
Base & reinforcement 4
Finishing & curing 3
Block, brick & mortar 5
Stucco & veneer 2
Popular sizes, already worked out
- How much concrete for a 10×10 slab1.36 cu yd with 10% extra (62 bags of 80 lb)
- How much concrete for a 12×12 slab1.96 cu yd with 10% extra (order 2 yd)
- How many yards of concrete for a 24×24 slab7.82 cu yd with 10% extra at 4 in
- How many 80 lb bags of concrete in a yard45 bags of 80 lb per cubic yard
- How many bags of concrete on a pallet42 bags of 80 lb (56 of 60 lb, 80 of 40 lb), Quikrete
- How much concrete for a 4×4 post3 bags of 80 lb (or 5 of 50 lb fast-setting) for a 10 in hole 3 ft deep
- How many bags of concrete for a 12 inch Sonotube6 bags of 80 lb for a tube 4 ft deep
- How much concrete does a truck hold8 to 12 cubic yards (about 6 to 9 m³)
- 8×8×16 block actual size7-5/8 × 7-5/8 × 15-5/8 in (194 × 194 × 397 mm)
- How many bricks per square foot6.75 modular bricks per sq ft (675 per 100 sq ft)
- How many bags of mortar per 100 block9 bags of 80 lb mortar mix (7.7 before the 15% extra)
- How much does a yard of concrete weighAbout 3,915 lb (140–150 lb per cu ft)
- How much does #4 rebar weigh per foot0.668 lb per foot (13.4 lb per 20 ft stick)
- How long before you can walk on concrete4 hours for fast-setting mix; about a day for standard concrete
Guides
- Concrete and masonry words, explainedPlain-English meanings of yield, slump, screed, control joint, curing, CMU, course, bond beam, scratch coat, rebar sizes, psi and more.
- Concrete bag yield chart: 40, 50, 60, 80 and 90 lb bagsHow much concrete each bag makes: 40 lb ≈ 0.30 cu ft, 60 lb ≈ 0.45, 80 lb ≈ 0.60 (Quikrete). Bags per yard, square feet per bag and bags per pallet.
- Cement vs concrete: what’s the difference, and which bag to buyCement is the binder; concrete is cement plus sand, gravel and water. What each bag at the store is for: concrete mix, portland cement, mortar, sand mix.
- Concrete block sizes: 8×8×16 actual size and the full CMU chartAn 8×8×16 concrete block is 7-5/8 × 7-5/8 × 15-5/8 in. Actual sizes of 4, 6, 8, 10 and 12 in CMU, half-high block, blocks per square foot and grout.
- Brick sizes chart: modular, queen, king, Norman and moreStandard brick sizes in inches and mm — modular 3-5/8 × 2-1/4 × 7-5/8 in, queen, king, Norman, utility — with bricks per square foot and mortar (BIA).
- Sonotube sizes chart: diameters, lengths and concrete per tubeSonotube sizes from 6 to 36 in, standard lengths, cubic feet and 80 lb bags of concrete per foot of tube, and cubic yards for common column heights.
Frequently asked questions
How do I work out how much concrete I need?
Multiply length (ft) × width (ft) × thickness (in) and divide by 12 for cubic feet, then by 27 for cubic yards. Add about 10% for spillage and an uneven base. A 10 × 10 ft slab 4 in thick is 1.23 cubic yards before the extra — worked through on how much concrete for a 10×10 slab.
How many 80 lb bags of concrete make a yard?
About 45. An 80 lb bag of Quikrete Concrete Mix yields roughly 0.60 cu ft, and a cubic yard is 27 cu ft. The concrete bag yield chart lists every bag size.
What is the difference between cement and concrete?
Cement is the grey powder that hardens when it reacts with water; concrete is cement mixed with sand, gravel and water. A bag of “concrete mix” already has the sand and gravel in it, which is what most people mean when they ask for cement. More in cement vs concrete.
Do the calculators work in metric?
Yes. Every calculator has a US / metric toggle and converts your entries when you switch. Metric bag sizes (20, 25 and 30 kg) are built in, and results show cubic metres and litres.
Will a calculator tell me how thick my footing or slab must be?
No. Footing size and depth, frost depth, slab thickness for structures and reinforcement are set by your local building code and your plans. The calculators count the concrete, block, steel and mortar for whatever those specify.
Where do the bag yields and coverages come from?
From manufacturer data sheets (Quikrete, Sakrete), industry technical notes (the Brick Industry Association and the Concrete Masonry & Hardscapes Association, formerly NCMA) and NRMCA’s guides to ready-mix. Each calculator lists its sources at the bottom of the page. Check the label on the bag you buy — yields vary a little between products.