Patio / Walk
1:2:3 · 3,000 PSI · w/c 0.50
Light foot traffic; standard residential mix
Concrete mix design · Updated 2026
Concrete Mix Ratio Calculator: Cement, Sand, Gravel & Water for Any Project
Calculate cement bags, sand, gravel, water, PSI strength, dry volume factor, ACI 318 exposure checks, and ready-mix cost comparison from project dimensions, standard mix ratios, or a custom ratio.
Why other calculators get this wrong
Many concrete mix calculators use a fixed dry volume factor of 1.54 for every mix. That factor fits lean mixes like 1:3:6 or 1:5:10, but richer mixes compact differently. CM-01 uses the dry factor assigned to each ratio, so a 1:2:3 mix uses 1.50 and a 1:1:2 mix uses 1.48.
Concrete Mix Ratios - 2026 Quick Reference
Most common: 1:2:3 (1 cement : 2 sand : 3 gravel), about 3,000 PSI for standard residential work.
| Material | Volume | Weight | Bags / Loads |
|---|---|---|---|
| Cement | 6.8 ft3 | 635 lb | 7 bags (94 lb) |
| Sand | 13.5 ft3 | 1350 lb | 0.50 yd3 |
| Gravel | 20.3 ft3 | 2126 lb | 0.75 yd3 |
| Water | - | 317 lb | 38.0 gallons |
Dry volume factor: 1.50, not a universal 1.54.
What are you building?
Water-cement ratio and buying settings
Mix
1:2:3 (M20)4.94 yd3 · dry factor 1.50
Cement
37 bags3,447 lb · 36.7 ft3
Water
206.6 gal5.58 gal per bag · w/c 0.50
Strength
7,000 PSI28-day estimate · M20
Results: six-dimensional output
| Material | Volume | Weight | Bags / Loads | Cost |
|---|---|---|---|---|
| Cement | 36.7 ft3 | 3,447 lb | 37 bags | $463 |
| Sand | 73.3 ft3 | 7,333 lb | 2.72 yd3 | $95 |
| Gravel | 110.0 ft3 | 11,550 lb | 4.07 yd3 | $183 |
| Water | - | 1,723 lb | 206.6 gal | - |
Dry volume factor used: 1.50, not a fixed 1.54. Finished wet volume: 4.94 yd3.
Strength development
3 days3,220 PSI
7 days4,900 PSI
14 days6,160 PSI
28 days7,000 PSI
90 days8,190 PSI
Cost vs ready-mix
Site-mixed materials: $741. Ready-mix at $145/yd3: $716.
Break-even point: about 5.1 yd3. Ready-mix is cheaper before labor value.
Brand reference: Quikrete Portland Cement 94 lb SKU #100015 and Sakrete Portland Cement 94 lb SKU #65200940.
Mix visualization
Cement16.7%
Sand33.3%
Gravel50.0%
By volume100%
Cement 16.7%Sand 33.3%Gravel 50.0%
By weight100%
Cement 15.4%Sand 32.8%Gravel 51.7%
ACI 318 compliance summary
OK · Interior use
w/c <= 0.60, PSI >= 2500
OK · Exterior (no F-T)
w/c <= 0.50, PSI >= 3000
Check · Freeze-thaw (F1)
w/c <= 0.45, PSI >= 3500
Check · Sulfate exposure
w/c <= 0.45, PSI >= 3500
OK · Watertight concrete
w/c <= 0.50, PSI >= 3000
OK · Structural minimum
ACI §19.2.1.1 PSI >= 2500
Concrete Mix Ratio Reference Table - All Standard Mixes (2026)
Per 1 cubic yard of finished concrete. 94 lb bags. Dry volume factor varies by mix.
| Mix Ratio | Grade | PSI | w/c | Dry Factor | Bags/yd3 | Sand ft3/yd3 | Gravel ft3/yd3 | Water gal/yd3 | Best For |
|---|---|---|---|---|---|---|---|---|---|
| 1:3:6 | M10 | 2,000 PSI | 0.60 | 1.54 | 5.0 | 12.5 | 24.9 | 28 | Blinding concrete, lean fill, non-structural |
| 1:2:4 | M15 | 2,500 PSI | 0.55 | 1.52 | 6.0 | 11.7 | 23.5 | 36 | Light non-structural slabs, paths |
| 1:2:3 | M20 | 3,000 PSI | 0.50 | 1.50 | 7.0 | 13.5 | 20.3 | 38 | Residential patios, walkways, general slabs |
| 1:1.5:3 | M25 | 3,500 PSI | 0.45 | 1.49 | 8.0 | 11.0 | 21.9 | 37 | Driveways, garage floors, foundations |
| 1:1:2 | M30 | 4,000 PSI | 0.42 | 1.48 | 10.0 | 10.0 | 20.0 | 47 | High-strength structural elements |
| 1:1:1.5 | M35 | 5,000 PSI | 0.38 | 1.47 | 12.0 | 11.3 | 17.0 | 49 | Commercial and industrial slabs |
| 1:0.5:1 | M40 | 6,000 PSI | 0.35 | 1.46 | 16.0 | 7.9 | 15.8 | 62 | High-performance engineered concrete |
Which Concrete Mix Ratio Should I Use? - Project Guide
Driveway
1:1.5:3 · 3,500 PSI · w/c 0.45
Vehicle loads; upgrade recommended
Garage Floor
1:1.5:3 · 3,500 PSI · w/c 0.45
Vehicles plus chemical exposure
Foundation
1:1.5:3 · 3,500 PSI · w/c 0.45
Structural; verify with engineer
Other
1:2:3 · 3,000 PSI · w/c 0.50
General purpose
Commercial / Industrial Floor
1:1:2 or 1:1:1.5 · 4,000-5,000 PSI
Heavy loads, forklifts, chemical resistance, and tighter w/c control.
Post Holes / Fence Posts
Pre-mixed fast-set
Small volumes are more practical with fast-set bagged products than site batching Portland cement.
Why the Dry Volume Factor Matters - And Why 1.54 Is Wrong for Most Mixes
The dry volume factor explained
Dry ingredients compact and fill voids after water is added, so the dry material volume must be larger than the finished wet concrete volume.
Lean mixes are aggregate-heavy and can justify a factor around 1.54. Richer mixes have more cement paste and lower void content, so the factor drops toward 1.47-1.50.
For a 20 x 20 ft, 4 in patio at 1:2:3, using 1.54 instead of 1.50 overstates dry material by about 2.7%.
| Mix Ratio | Dry Factor | Error if using 1.54 |
|---|---|---|
| 1:3:6 | 1.54 | 0% |
| 1:2:4 | 1.52 | +1.3% overestimate |
| 1:2:3 | 1.50 | +2.7% overestimate |
| 1:1.5:3 | 1.49 | +3.4% overestimate |
| 1:1:2 | 1.48 | +4.1% overestimate |
| 1:1:1.5 | 1.47 | +4.8% overestimate |
How to Mix Concrete: Hand Mixing vs. Drum Mixer vs. Ready-Mix
| Method | Best Volume | Time | Cost | Quality | When to Use |
|---|---|---|---|---|---|
| Hand mixing (wheelbarrow) | < 0.3 yd3 | Slow | Lowest | Variable | Post holes, small repairs |
| Drum mixer (rented) | 0.3-1.5 yd3 | Medium | Low | Good | Patios, small slabs |
| Ready-mix truck | > 1.5 yd3 | Fast | Medium | Best | Driveways, garage floors |
| Volumetric mixer | Any | Fast | Medium | Excellent | Large or phased pours |
1
Measure all dry ingredients by volume with the same bucket.
2
Mix dry cement, sand, and gravel until color is uniform.
3
Make a crater in the center of the dry mix.
4
Add 75% of water first and mix from outside in.
5
Add remaining water gradually; stop when the mix holds shape.
6
Squeeze test: it should hold form without dripping.
7
Place within 30-45 minutes of mixing.
Concrete Mix Ratio Calculator FAQ
What is the best concrete mix ratio for a patio?+
The standard concrete mix ratio for a residential patio is 1:2:3 (1 part cement : 2 parts sand : 3 parts gravel), producing approximately 3,000 PSI. For freeze-thaw climates, upgrade to 1:1.5:3 with w/c = 0.45.
How much cement, sand, and gravel do I need per cubic yard?+
For 1:2:3 mix: about 7 bags of 94-lb cement, 13.5 ft3 of sand, 20.3 ft3 of gravel, and 37 gallons of water per cubic yard before waste.
What is the difference between 1:2:3 and 1:1.5:3 concrete mix?+
1:2:3 is a 3,000 PSI general residential mix at w/c 0.50. 1:1.5:3 uses more cement and less water, targets about 3,500 PSI, and is better for driveways, garage floors, freeze-thaw exposure, and foundations.
What does M20 concrete mean, and is it the same as 1:2:3?+
M20 means concrete with about 20 MPa characteristic compressive strength at 28 days, roughly 2,900-3,000 PSI. In US practice, 1:2:3 is commonly treated as a 3,000 PSI nominal mix, but formal M20 design can differ by code.
Should I use bags or ready-mix concrete for my project?+
Use bagged or site-mixed material for small staged pours under about 1.0-1.5 yd3. Use ready-mix when volume exceeds 1.5 yd3 or the slab needs a continuous pour without cold joints.
Can I use a different sand-to-gravel ratio?+
Yes, within practical limits. Cement content and water-cement ratio control strength most directly, while sand-to-gravel balance affects workability, finishability, and aggregate packing.
What happens if I add too much water to the concrete mix?+
Extra water lowers strength, increases shrinkage cracking, increases permeability, and leaves a weaker surface. If the mix is too stiff, use a water reducer or adjust the next batch rather than adding water freely.
Related Tools
For cement-only quantities, use the cement calculator. For strength checks, use the concrete PSI calculator or water-cement ratio calculator. Volume planning belongs in the concrete calculator and reinforcement in the rebar calculator.
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