Concrete Mix Ratio Chart
Volumetric proportions of cement, sand and coarse aggregate for each target strength, with the water-cement ratio that goes with it and the work each mix suits.
Quick answer
Mix ratios by target strength
| Strength | Cement : Sand : Aggregate | Water-cement ratio | Cement per yd³ (approx) | Typical use |
|---|---|---|---|---|
| 2,000 psi | 1 : 3 : 6 | 0.70 | 2.7 ft³ ≈ 254 lb | Non-structural fill, mud slabs, bedding |
| 2,500 psi | 1 : 2.5 : 5 | 0.65 | 3.18 ft³ ≈ 299 lb | Footings and foundation walls in mild climates |
| 3,000 psi | 1 : 2.5 : 4 | 0.58 | 3.6 ft³ ≈ 338 lb | Patios, walkways, interior slabs, footings |
| 3,500 psi | 1 : 2 : 4 | 0.53 | 3.86 ft³ ≈ 363 lb | Driveways and garage slabs |
| 4,000 psi | 1 : 2 : 3 | 0.48 | 4.5 ft³ ≈ 423 lb | Driveways in freeze-thaw climates, shop floors |
| 4,500 psi | 1 : 1.5 : 3 | 0.44 | 4.91 ft³ ≈ 461 lb | Heavy vehicle areas, structural slabs |
| 5,000 psi | 1 : 1.5 : 2.5 | 0.40 | 5.4 ft³ ≈ 508 lb | Columns, beams, heavy industrial floors |
How to read these ratios
The numbers are parts by volume, measured with the same bucket: 1 : 2 : 3 means one bucket of portland cement, two of sand, three of gravel. A 1 : 2 : 3 mix therefore has six total parts, so cement is one sixth of the batch volume before water.
Water is the variable people get wrong. The water-cement ratio in the table is by weight, so a 0.48 ratio on 94 lb of cement is about 45 lb of water — five and a half gallons. Wet, soupy concrete is easier to place and measurably weaker; if it is too stiff, the fix is more paste (cement and sand), not more water.
Aggregate size matters too. Coarse aggregate should not exceed one third of the slab thickness or three quarters of the clear space between reinforcing bars, or the mix will bridge instead of consolidating.
Source & method: Proportions are the long-standing nominal volumetric site mixes (1 : 3 : 6 through 1 : 1.5 : 2.5) and the established inverse relationship between water-cement ratio and compressive strength. Cement quantity per cubic yard is derived arithmetically from the batch proportion. No copyrighted specification table is reproduced.
Mixing equipment
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- Magnesium bull floatFlattens and closes the surface right after screeding.Every slab · Check price
- Screed board / power screedStrikes the slab to grade before it starts to set.Slabs · Check price
- Concrete mixer (1.5–4 cu ft)Faster and more consistent than mixing bags in a wheelbarrow.Bagged pours · Check price
- Contractor wheelbarrow6 cu ft steel tray moves roughly 300 lb of wet mix per trip.Every pour · Check price
- Edger, groover and steel trowelRadius the edges and cut control joints before the slab hardens.Finishing · Check price
- Rubber boots and nitrile glovesWet concrete is caustic — cover skin before you stand in it.Safety · Check price
Frequently asked questions
- What is the ratio for 3000 psi concrete?
- A 1 : 2.5 : 4 mix by volume — one part cement, two and a half parts sand, four parts coarse aggregate — with a water-cement ratio near 0.58. That is the common mix for patios, walkways and residential footings.
- What is the standard concrete mix ratio?
- 1 : 2 : 3 (cement : sand : gravel) is the general-purpose site mix and lands around 4,000 psi at a 0.48 water-cement ratio. Weaker fill mixes go to 1 : 3 : 6, and higher-strength work tightens toward 1 : 1.5 : 2.5.
- What does the water-cement ratio do?
- It sets the strength. Less water per unit of cement gives higher strength and lower permeability, which is why 0.40 mixes reach 5,000 psi and 0.70 mixes struggle past 2,000. Adding water on site to make concrete easier to place directly reduces the strength you paid for.
- How much cement do I need per cubic yard?
- A 3,000 psi mix uses roughly 5 to 5.5 sacks of cement per cubic yard, about 470 to 520 lb. A 4,000 psi mix runs 6 to 6.5 sacks. Bagged mixes have the cement already proportioned in.
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- Gravel CalculatorTons and cubic yards of gravel, crushed stone or road base for any area.