M20 Concrete Calculator
This M20 concrete calculator batches M20 grade concrete — characteristic strength 20 MPa (≈ 2,900 psi) at 28 days — using its nominal 1:1.5:3 mix. Enter the volume you need and get cement bags, sand and aggregate.
How to Use This Calculator
- Enter your dimensions — feet for lengths, inches for thickness.
- Adjust the options — waste percentage, bag size and your local concrete price.
- Read your results — volume, bags, weight and cost update live as you type.
The Formula
M20 nominal mix = 1:1.5:3 (cement : sand : aggregate), dry volume factor 1.54 Worked example: For 1 m³ of M20: 1.54 m³ dry material split 1:1.5:3 — the calculator returns exact cement bags, sand and aggregate volumes and masses.
M20 concrete is the workhorse residential grade — slabs, footings, driveways and beams in normal exposure. The "M" is for mix; the number is the characteristic cube strength in MPa at 28 days.
A concrete calculator m20 batch at the nominal 1:1.5:3 ratio consumes roughly 8 × 50 kg cement bags per cubic meter. M20 is the minimum grade most codes allow for reinforced concrete.
Nominal mixes are a site convenience, not a lab design: for structural work specified by an engineer, order a designed mix from a ready-mix plant and use this calculator for volume and cost checks.
Frequently Asked Questions
Common questions about the m20 concrete calculator.
What does M20 mean?
Mix grade with characteristic compressive strength of 20 MPa (≈ 2,900 psi) at 28 days, tested on 150 mm cubes.
What is the ratio for M20 concrete?
The nominal mix is 1:1.5:3 (cement : sand : aggregate) by volume. Designed mixes achieving M20 vary by materials and admixtures.
Where is M20 used?
The workhorse residential grade — slabs, footings, driveways and beams in normal exposure.
How much cement per m³ of M20?
Enter 1 m³ above — the calculator returns the exact 50 kg bag count for the 1:1.5:3 nominal mix (roughly 8 bags).
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