REFERENCE TABLE · CONSTRUCTION · CONCRETE
Every standard nominal mix from M5 (1:5:10) to M25 (1:1:2): the ratio, the 28-day strength in MPa and psi, typical uses, and water–cement guidance — cross-checked across published tables. The calculator does the yard math: 1 yd³ of M20 needs 5.9 bags of cement, 11.2 ft³ of sand, 22.4 ft³ of coarse aggregate, and 42.1 gallons of water. The full printable chart is under the calculator.
Enter the wet volume in cubic feet or cubic yards and pick a nominal mix grade. The calculator applies the 1.52 dry-volume factor, splits the dry volume by the grade’s cement : sand : aggregate ratio, and returns 94-lb cement bags (about 1.27 ft³ each), sand and aggregate in ft³, and water in gallons at the grade’s water–cement ratio.
The number after M is the 28-day strength in MPa; the ratio is by volume. M20 = 20 MPa (~2,901 psi) at a 1:1.5:3 cement : sand : coarse-aggregate ratio, and it’s the workhorse for footings, slabs, and beams. Default check: 1 yd³ M20 = 27 ft³ wet × 1.52 = 41.04 ft³ dry, split 1:1.5:3 (5.5 parts) into 7.46 ft³ cement → 5.9 bags, 11.19 ft³ sand, 22.39 ft³ aggregate, and 42.1 gallons of water at a 0.50 water–cement ratio. Nominal mixes are field recipes, not engineered designs — use them up to M20 for non-critical work; M25 and up belong to a proper design mix.
Ratios are cement : sand : coarse aggregate by volume, cross-checked across published nominal-mix tables. The grade number is the characteristic 28-day compressive strength in MPa; psi is MPa × 145.038. Print-friendly — use the print button above the calculator.
| Mix grade | 28-day strength (MPa / psi) | Nominal ratio (cement : sand : aggregate) | Typical use | Max water–cement ratio |
|---|---|---|---|---|
| M5 | 5 / 725 | 1 : 5 : 10 | Blinding/lean concrete, bedding under footings | 0.60 |
| M7.5 | 7.5 / 1,088 | 1 : 4 : 8 | Lean concrete, PCC work, mass concrete | 0.55 |
| M10 | 10 / 1,450 | 1 : 3 : 6 | Mass concrete, levelling courses, non-structural | 0.55 |
| M15 | 15 / 2,176 | 1 : 2 : 4 | Plain concrete, mass foundations, floor screeds | 0.50 |
| M20 | 20 / 2,901 | 1 : 1.5 : 3 | Footings, slabs, beams — the all-rounder | 0.50 |
| M25 | 25 / 3,626 | 1 : 1 : 2 | Slabs, columns, structural concrete (nominal limit) | 0.45 |
US readers: a ready-mix ticket for 3,000 psi is roughly an M20-class mix, and 4,000 psi sits above M25 — but American practice orders designed mixes by specified strength, not these nominal ratios. Never hand-mix nominal 1:1:2 and call it 4,000-psi structural concrete; above M20, use a batch-plant designed mix or an engineer’s spec.
Setup: 1 yd³ of M20 (ratio 1:1.5:3, water–cement ratio 0.50).
Line 1 — dry volume. 1 yd³ = 27 ft³ wet. Dry ingredients occupy 1.52× the wet volume: 27 × 1.52 = 41.04 ft³ of dry material to batch.
Line 2 — the split. 1 + 1.5 + 3 = 5.5 parts. Cement = 41.04 × 1/5.5 = 7.46 ft³. Sand = 41.04 × 1.5/5.5 = 11.19 ft³. Aggregate = 41.04 × 3/5.5 = 22.39 ft³.
Line 3 — bags and water. Cement: 7.46 ft³ ÷ 1.27 ft³/bag = 5.9 bags of 94-lb cement. Water: 7.46 ft³ × 94 lb/ft³ = 701.4 lb cement × 0.50 = 350.7 lb ÷ 8.34 lb/gal = 42.1 gallons.
Branch — the footing (½ yd³ of M25): dry = 13.5 × 1.52 = 20.52 ft³; ratio 1:1:2 (4 parts) → 4.0 bags cement, 5.13 ft³ sand, 10.26 ft³ aggregate, 26.0 gallons water at a 0.45 w/c.
Branch — the slab (54 ft³ = 2 yd³ of M15): dry = 54 × 1.52 = 82.08 ft³; ratio 1:2:4 (7 parts) → 9.2 bags cement, 23.45 ft³ sand, 46.90 ft³ aggregate, 66.1 gallons water at a 0.50 w/c.
Note on SI: this page works in imperial units. For metric jobs, 1 m³ = 35.3147 ft³ — convert your cubic meters to ft³ first, then run the calculator.
| Output | Formula | What it means |
|---|---|---|
| Cement bags (94 lb) | dry volume × cement share ÷ 1.27 ft³/bag | 5.9 bags at the defaults — the bag count you buy (round up to whole bags at the store). |
| Sand (ft³) | dry volume × sand share | 11.19 ft³ at the defaults — order by the cubic yard or by the half-yard scoop. |
| Coarse aggregate (ft³) | dry volume × aggregate share | 22.39 ft³ at the defaults — the gravel/stone fraction; keep it clean and well-graded. |
| Water (gallons) | cement weight × w/c ratio ÷ 8.34 lb/gal | 42.1 gal at the defaults — a maximum, not a target: add water last and stop when the mix is workable. |
The ratios in the chart are the standard nominal mixes (1:5:10 for M5 through 1:1:2 for M25), cross-checked across multiple published tables — they are field conventions, not lab-verified designs. The 1.52 dry-volume factor is the industry rule of thumb for the voids in dry ingredients; real aggregate voids vary with gradation and moisture. A 94-lb bag is taken as 1.27 ft³ (loose), cement density as 94 lb/ft³, and water as 8.34 lb/gal. Water figures are maximums at the listed w/c ratio — batch with less if the mix is workable, and account for damp aggregate. Nominal mixes are not a substitute for a designed mix on structural work, and this page does not size concrete for your project — follow your engineer’s spec and local code.
Bright Side Kit. "Concrete Mix Ratio Chart: M5–M25 With Pour Calculator." https://brightoolbox.com/concrete-mix-ratio-chart/ Accessed October 24, 2026.Data sourcesDry ingredients have voids; wet concrete doesn’t. A cubic yard of loose cement, sand, and stone contains roughly 52% empty air space between particles, which the cement paste fills when mixed. The industry-standard factor 1.52 converts wet placed volume back to the dry volume you must batch — skip it and you’ll come up about a third short.
Nominal = fixed recipe; design = engineered recipe. Nominal mixes like 1:1.5:3 are published conventions that work for ordinary, non-critical concrete up to about M20. A design mix is proportioned in a lab for a specific strength, aggregate, and exposure — required for M25 and above and all structural work where the strength is specified.
For light, non-engineered footings it’s the traditional choice — but M20 (1:1.5:3) is the safer default. 1:2:4 was the classic hand-mix footing recipe for decades. Modern practice favors M20 for anything carrying a real structure, and any engineered drawing will specify its own mix. When in doubt, batch the stronger grade — the cement costs little, the regret costs a lot.
Bags for anything under ~5 yards; bulk beyond that. The calculator outputs 94-lb bags because that’s how DIY and small jobs buy cement — 5.9 bags for a yard of M20. Above roughly 5 cubic yards, ready-mix delivery or bulk silo cement beats hand-mixing on price, consistency, and your back.
3,000 psi ≈ M20 class; 4,000 psi is beyond M25. The MPa-to-psi line: M20 = 20 MPa ≈ 2,901 psi, M25 = 25 MPa ≈ 3,626 psi. US practice orders by specified strength on the ticket, not by nominal ratio — so translate the chart for understanding, but order the ticket in psi and never hand-mix nominal ratios for 4,000-psi structural work.