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Concrete

Concrete Mix Ratio Calculator USA 2026

Break down a concrete pour into the cement, sand and gravel volumes required for a standard 1:2:3 mix.

Reviewed by BuildMate Editorial Team Construction Researchers Updated March 2026 2 min read Fact-checked

Used by

250,000+ homeowners

Avg. time

~15 seconds

Updated

2026

Accuracy

Pro estimation

Works on: Desktop Tablet Mobile No registration required
Unit system

Enter your measurements

Results

Dry material volume

41.58 ft³

Cement

6.93 ft³

7 × 94 lb bags

Sand

13.86 ft³

Gravel / stone

20.79 ft³

Calculation steps
  1. 1.Dry volume = 27 × 1.54 = 41.58 ft³
  2. 2.1 part cement = 41.58 ÷ 6 = 6.93 ft³
  3. 3.2 parts sand = 13.86 ft³
  4. 4.3 parts gravel = 20.79 ft³

Includes a standard waste allowance. Verify with your supplier before ordering.

Stored on this device — no account needed.

What this calculator does

Estimates the volume of ready-mix concrete you need — in cubic yards, cubic meters and 60/80 lb bag counts — plus a 10% waste allowance so you don't run short mid-pour.

When to use it

  • Planning a slab, patio, footing, driveway or sidewalk pour.
  • Comparing bagged vs. ready-mix truck pricing.
  • Sizing rebar, mesh and vapor barrier by area.

Common mistakes

  • Forgetting to convert thickness from inches to feet before multiplying.
  • Ordering exact volume with zero waste — always add 5–10%.
  • Ignoring compaction: over-excavated subgrade sinks the finished slab.

Pro tips

  • Order 10% extra for slabs, 15% for uneven ground or complex forms.
  • For driveways, use 6" thickness and #4 rebar at 18" on-center.
  • Pour early morning in summer to avoid flash-set from heat.
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Disclaimer: Estimates based on 2026 RSMeans USA data. Actual quantities vary by site conditions, waste and installer practices. Verify with your supplier or contractor before ordering.

How it works

  1. 1Enter the finished (wet) volume you need in cubic feet.
  2. 2We multiply by 1.54 to get dry ingredient volume, then split 1:2:3.

Formula

1 : 2 : 3 by volume, dry-material factor 1.54

Worked example

27 ft³ pour × 1.54 = 41.6 ft³ dry → 6.9 cement, 13.9 sand, 20.8 gravel.

Frequently asked questions

Why 1.54?

Dry ingredients pack tighter when wet; 1.54 is the accepted dry-to-wet volume factor.

What's a good mix for slabs?

1:2:3 (cement : sand : gravel) with 0.5 water/cement ratio ≈ 3000 psi.

Is the Concrete Mix Ratio Calculator free to use?

Yes — every BuildMate calculator is 100% free, requires no signup and works offline once the page has loaded.

How accurate are these estimates?

Formulas follow 2026 industry standards (RSMeans, ICC and manufacturer specs). Real-world results vary by site conditions, waste and installer practices — always get 2–3 written quotes from licensed pros before committing.

Can I save my calculation?

Yes. Hit the Save button after you run an estimate — it's stored on this device (no account needed) and you can access it anytime from the Saved drawer.

Can I compare two projects side-by-side?

Yes. Add estimates to Compare and open the Compare drawer to see them side-by-side, then use Download PDF or Email to share the comparison.

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