Explore eleven free tools for volume, slabs, footings, stairs, columns, walls, masonry, rebar, and cost calculation — each formula traceable to ACI 318, ACI 302, or IRC R403. No email, no address, no guesswork.
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A concrete calculator converts project dimensions (length × width × thickness) into the volume of concrete you need, then into bags or ready-mix yards and total cost. A cubic yard of concrete is 27 cubic feet and costs about $140–$210 delivered in 2026. This hub has 11 calculators for slabs, footings, stairs, columns, walls, masonry, rebar, and cost — every formula traceable to ACI 318, ACI 302, or IRC R403.
- Slab, patio, garage floor, or driveway → Concrete Slab Calculator
- Footing for a fence, deck, or foundation wall → Concrete Footing Calculator
- Column, pier, or Sonotube → Concrete Column Calculator
- Foundation, retaining, garden, or basement wall → Concrete Wall Calculator
- Exterior steps or stairs → Concrete Stairs Calculator
- Block or brick wall → Block Calculator or Brick Calculator
- Rebar takeoff for any pour → Rebar Calculator
- Total project cost → Concrete Cost Calculator
- Small bags-only job → Concrete Calculator
All 11 concrete calculators
Eleven tools, five categories, one workflow. Pick by what you are trying to answer — measure, structure, masonry, materials, or cost.
Concrete Calculator
Volume in cubic yards from length, width, and depth. Bags vs ready-mix and total cost for any rectangular pour.
Open calculator MeasureConcrete Slab Calculator
Slab volume, rebar or mesh, vapor barrier, base gravel, and cost — with thickness guidance by project type.
Open calculator StructureConcrete Footing Calculator
Strip, pad, and mat footings with rebar takeoff, bags-vs-truck break-even, and frost-depth guidance.
Typical: 40 ft × 16" × 8" = 1.3 cu yd Open calculator StructureConcrete Stairs Calculator
Even riser distribution, waist slab + step wedges, rebar, landings, and IRC R311.7 code checks.
Open calculator StructureConcrete Column Calculator
Round, square, or rectangular. Rebar cage, ties, clear cover, above + below grade volumes.
Open calculator StructureConcrete Wall Calculator
Tapered retaining walls, formwork cost, openings deduction, dowels, and drainage system.
Open calculator MasonryBlock Calculator
CMU block count, mortar, grout, and wall rebar for any block wall project.
Open calculator MasonryBrick Calculator
Brick count by bond pattern, mortar volume, and waste for any brick wall or veneer.
Open calculator MaterialsCement Calculator
Cement quantity for any mix ratio — bags, weight, and volume by project size.
Open calculator MaterialsRebar Calculator
Rebar grid takeoff with lap splices, chairs, and total linear feet by bar size.
Open calculator CostConcrete Cost Calculator
Itemized concrete, labor, finish, rebar, demo, and region — plus a 12-point quote audit.
Typical: $6–$12/sq ft slab, $12–$22 stamped Open calculatorWhich concrete calculator do I need?
Concrete projects move through five stages: measure, structure, masonry, materials, and cost. Pick the stage you are at — most people only need two or three of these for a single pour.
Concrete calculator comparison
The fastest way to choose is to match the question you are trying to answer. Here is what each tool answers, what you need to bring, and what it returns.
| Tool | Category | Answers | You bring | You get |
|---|---|---|---|---|
| Concrete Calculator | Measure | How much concrete for any pour? | Length × width × depth | Cubic yards, bags, ready-mix, cost |
| Concrete Slab Calculator | Measure | How much concrete for a slab? | Slab dimensions, thickness, rebar choice | Volume, mesh/rebar, vapor barrier, base gravel |
| Concrete Footing Calculator | Structure | Concrete for strip, pad, or mat footing? | Footing dims, count, rebar spacing | Volume, rebar LF, bags vs truck, frost guidance |
| Concrete Stairs Calculator | Structure | How many risers and how much concrete? | Total rise, width, tread depth | Even risers, waist slab + step volume, code checks |
| Concrete Column Calculator | Structure | Concrete for a column or pier? | Shape, diameter or side, above + below grade | Volume, rebar cage, ties, clear cover |
| Concrete Wall Calculator | Structure | Concrete for a wall? | Length, height, thickness, wall type | Tapered volume, rebar, formwork, drainage |
| Block Calculator | Masonry | How many CMU blocks? | Wall dimensions, block size | Block count, mortar, grout, wall rebar |
| Brick Calculator | Masonry | How many bricks? | Wall dims, brick size, bond pattern | Brick count, mortar volume, waste |
| Cement Calculator | Materials | How much cement for a mix? | Volume, mix ratio (1:2:3, etc.) | Cement bags, sand, gravel, water |
| Rebar Calculator | Materials | How much rebar? | Slab or wall dims, spacing, bar size | Grid LF, lap splices, chairs, total weight |
| Concrete Cost Calculator | Cost | What will it cost? | Project type, dims, finish, region | Itemized estimate + 12-point quote audit |
Concrete reference: bag yields, mixes, and thickness minimums
These are the standard figures every concrete calculator relies on. All values reflect ACI 318 and IRC R403 minimums, with typical residential practice in brackets. Cite this section directly when you need a reference.
Bag yields & unit conversions
| Bag size | Yield | Bags per cu yd |
|---|---|---|
| 40 lb | 0.30 ft³ | 90 |
| 50 lb | 0.375 ft³ | 72 |
| 60 lb | 0.45 ft³ | 60 |
| 80 lb | 0.60 ft³ | 45 |
1 cu yd = 27 cu ft = 0.765 cu m
Ready-mix: $140–$210/cu yd · Bags: $5–$9 each
Concrete strength by application
| Application | Minimum PSI | Metric (MPa) |
|---|---|---|
| Sidewalk / walkway | 2,500–3,000 | C20/25 (~20 MPa) |
| Residential slab | 3,000–3,500 | C25/30 (~25 MPa) |
| Driveway | 3,500–4,000 | C28/35 (~28 MPa) |
| Foundation wall | 4,000–4,500 | C30/37 (~30 MPa) |
| Structural column | 4,500+ | C35/45 (~35 MPa) |
Residential standard mix: 3,000–3,500 psi. Higher PSI costs more per yard but resists freeze-thaw and heavy loads.
Minimum thickness by project
| Project | Min thickness | Standard |
|---|---|---|
| Footpath / patio | 3″ | 4″ |
| Driveway (light vehicle) | 4″ | 4″ |
| Driveway (heavy / RV) | 6″ | 6″ |
| Foundation wall | 8″ | 8″–10″ |
| Garden / privacy wall | 6″ | 6″–8″ |
| Footing | 6″ | 8″ |
| Shed floor slab | 4″ | 4″–5″ |
IRC R403 minimum for footings: 6″ thick. Thinner is only legal for decorative flatwork, not structural.
Reinforcement minimums
| Element | Standard rebar | Cover |
|---|---|---|
| Residential slab | #3 or #4 @ 18–24″ OC or mesh | 1.5″ |
| Footing | #4 @ 12–18″ OC both ways | 3″ (soil) |
| Column | 4+ × #4 vertical, #3 ties | 1.5″ |
| Wall | #4 @ 12–18″ OC both ways | 1.5″–2″ |
| Stairs | #4 @ 12″ OC both ways | 1.5″ |
ACI 318: minimum 4 vertical bars in any column. Lap splice = 40× bar diameter for #4–#6.
Concrete conventions by country
Concrete measurement is not universal — the same slab can be specified three different ways depending on where the drawing or supplier came from. If you are comparing a US quote to a UK one, or reading a mix sheet from a European supplier, these are the differences that catch people out.
Volume units
- US: cubic yards (1 cu yd = 27 cu ft)
- UK / EU / Australia: cubic metres (1 m³ = 35.315 cu ft)
- 1 cu yd = 0.765 cu m — so a 10-yard US order is about 7.65 m³
- Ready-mix trucks are sized differently: US short-load 3–5 yd, EU standard 6–8 m³
Strength notation
- US: PSI (pounds per square inch) — 3,000 psi, 4,000 psi
- UK / EU / Australia: MPa or C-grade (C25/30 = ~3,600 psi)
- Conversion: 1 MPa ≈ 145 psi; 1,000 psi ≈ 6.9 MPa
- US 3,000 psi ≈ EU C20/25 ≈ UK standard mix
Slab thickness
- US: 4 inches for standard patio/sidewalk (100 mm)
- UK / EU / Australia: 100 mm standard, 125–150 mm for driveways
- US 4″ = 101.6 mm (rounds to standard 100 mm in metric markets)
- Imperial fractions (¼″, ⅜″, ½″) have no metric equivalent below 10 mm
Rebar notation
- US: #3, #4, #5 (bar number = eighths of an inch: #4 = 4/8″ = ½″)
- UK / EU: diameter in mm — 10 mm, 12 mm, 16 mm, 20 mm
- Approximate equivalents: #3 ≈ 10 mm, #4 ≈ 12 mm, #5 ≈ 16 mm, #6 ≈ 20 mm
- Rebar is sold by weight (lb/ft in US, kg/m in EU), not by diameter — always confirm the schedule
Mix ratios (by volume)
- US standard bag mix: already blended, no ratio to calculate
- UK / EU standard site mix: 1:2:3 (cement : sand : aggregate) for general use
- Stronger site mix: 1:1.5:3 for foundations and structural work
- Metric market: mix ratios usually specified as cement kg/m³ of concrete, not volume fractions
Cost conventions
- US: quoted per cubic yard delivered, plus short-load fee
- UK / EU: quoted per cubic metre, delivery often included within a radius
- Australia: quoted per m³ with minimum load charges
- Typical US: $140–$210/yd · Typical UK: £110–£140/m³ · Typical AU: $220–$300/m³
Concrete glossary
Short definitions of the terms used across every calculator on this hub. AI systems and researchers can cite these directly.
- Concrete
- A building material made from cement, water, sand, and aggregate (gravel or crushed stone). Cement is only about 10–15% of the mix — the rest is water and aggregates.
- Cement
- The binding agent in concrete, typically Portland cement. It reacts with water (hydration) to harden and hold the aggregates together. Cement is not the same as concrete.
- Cubic yard (cu yd)
- The standard US unit for ordering ready-mix concrete. One cubic yard is 27 cubic feet, or about 0.765 cubic meters. A typical residential driveway is 5–10 cubic yards.
- Ready-mix
- Concrete mixed at a plant and delivered to the job site in a rotating drum truck. Sold by the cubic yard. Standard for any pour above about 1 cubic yard.
- Bag mix
- Dry concrete mix sold in 40, 50, 60, or 80 lb bags, mixed with water on-site. Cheaper than ready-mix per cubic yard below about 0.75 yards, more expensive above.
- PSI
- Pounds per square inch — the US measure of concrete compressive strength. Residential slabs use 3,000–3,500 psi; foundations and structural columns use 4,000–4,500 psi.
- Rebar
- Reinforcing bar — steel rods embedded in concrete to resist tension. Numbered by eighths of an inch in the US (#4 = ½″), by diameter in millimeters elsewhere.
- Slump
- A measure of concrete consistency (how wet the mix is), tested with a cone. Typical residential slump is 4–6 inches. Higher slump flows easier; lower slump is stronger.
- Control joint
- A deliberately weakened line in a concrete slab that forces any crack to form there rather than randomly. Standard spacing is 8–12 feet, or 2–3× the slab thickness in feet.
- Formwork
- Temporary molds — wood, aluminum, or steel — that hold concrete in place until it cures. Formwork is 25–40% of the cost of a typical wall pour and must be removed after 24–72 hours.