Concrete Mix Ratio Calculator: Cement, Sand and Gravel
A standard hand-mixed concrete uses 1 part Portland cement, 2 parts sand and 3 parts gravel by volume (Quikrete); the calculator turns your volume into bags of cement and cubic feet of sand and gravel.
Free · No sign-up
7 bags of 94 lb cement
- Dry materials (× 1.54)
- 41.58 ft³
- Cement
- 6.93 ft³
- Sand
- 13.86 ft³
- Gravel
- 20.79 ft³
Key takeaways
- Standard hand mix: 1 cement : 2 sand : 3 gravel by volume.
- One yard of 1:2:3 needs about 7 bags of 94 lb cement.
- Too much water makes weak concrete.
- Residential strength: 2,500–3,500 psi (IRC).
What Is the Ratio of a Concrete Mix?
The standard concrete mix ratio is 1 part cement, 2 parts sand and 3 parts gravel by volume, the hand-mix ratio on Quikrete's Portland cement page and the "old rule of thumb" in the University of Illinois materials science guide.
How to Calculate Concrete Mix Materials
- Find the wet concrete volume in cubic feet.
- Multiply by 1.54 for the dry volume (a common rule of thumb).
- Divide the dry volume by the total parts (6 for 1:2:3).
- Multiply one part by 1, 2 and 3 for cement, sand and gravel.
- Divide the cement by about 1 ft³ per 94 lb bag.
What Is the 1.54 Factor in Concrete?
The 1.54 factor converts wet concrete volume to the dry volume of cement, sand and gravel you need, because dry materials shrink when water fills their voids; it is a common rule of thumb (Civil Practical Knowledge), not a code value.
1:2:3 vs 1:2:4 Concrete Mix
A 1:2:4 mix uses less cement per yard than 1:2:3, so it is leaner. For one cubic yard (27 ft³ wet):
| Material | 1:2:3 | 1:2:4 |
|---|---|---|
| Cement bags (94 lb) | 7 | 6 |
| Cement | 6.93 ft³ | 5.94 ft³ |
| Sand | 13.86 ft³ | 11.88 ft³ |
| Gravel | 20.79 ft³ | 23.76 ft³ |
These are rule-of-thumb volumes; the 1.54 dry factor and 1 ft³ per cement bag are secondary estimates.
Concrete Mix Ratio for a Slab, Driveway and Fence Posts
Slabs, driveways and fence posts commonly use the same 1:2:3 hand mix; what changes is the strength the code asks for. The 2021 IRC sets 2,500 psi for interior slabs and up to 3,500 psi for garage floors and exposed steps in severe weathering regions (Table R402.2), so for driveways and garages a tested premix or ready-mix is the safer choice.
How Much Water to Mix Concrete?
Add only enough water to make the mix workable: too much water makes weak concrete and too little makes it unworkable, according to the University of Illinois guide. For premix bags, follow the water amount on the bag.
Mix Ratio by Volume vs by Weight
Proportioning by volume is quicker but less accurate than by weight, according to the University of Illinois guide. Hand mixes use volume (shovels or buckets); plants batch by weight.
Mixing Your Own vs Premix Bags
Premix bags remove the measuring step and give a rated strength, such as 4,000 psi for Quikrete Concrete Mix; mixing your own needs separate cement, sand and gravel. Count premix bags with the bags of concrete calculator.
Worked Examples: Materials for Three Pours
One cubic yard at 1:2:3. 27 ft³ × 1.54 = 41.58 ft³ dry ÷ 6 = 6.93 ft³ per part: 7 bags of cement, 13.86 ft³ sand, 20.79 ft³ gravel.
A 10×10 slab at 4 in (33.33 ft³). 51.3 ft³ dry: about 9 bags of cement, 17.1 ft³ sand, 25.7 ft³ gravel.
One fence post (1.40 ft³). 2.16 ft³ dry: about ⅓ bag of cement; a premix bag is simpler.
How to Mix Concrete by Hand
- Measure the cement, sand and gravel by volume with the same bucket.
- Blend the dry materials first.
- Add water slowly until the mix is workable, not too stiff or too sloppy (University of Illinois).
- Place it right away and keep it moist while it cures (NRMCA CIP 11).
Types of Concrete Mix and Their Uses
Bagged mixes differ by strength, set time and stone size, and each one suits a different job.
| Mix (Quikrete) | What the maker says | Typical use |
|---|---|---|
| Concrete Mix (No. 1101) | 4,000 psi average compressive strength | Slabs, footings, steps |
| Fast-Setting Concrete Mix (No. 1004) | Sets hard in about 20 to 40 minutes | Fence and mailbox posts |
| Countertop Mix (No. 1106) | Flowable, 6,000 psi at 28 days | Cast countertops |
| Mortar Mix (No. 1102) | Type N mortar, ASTM C 270 | Laying block and brick (not structural concrete) |
Values come from Quikrete's product pages; other brands sell similar mixes under their own names. See Sakrete vs Quikrete.
Concrete Mix Ratio Calculator FAQ
What is a 1-2-3 concrete mix?
A 1-2-3 mix is 1 part cement, 2 parts sand and 3 parts gravel by volume, the standard hand mix.
How long does concrete take to reach 75% strength?
Concrete gains about 70% of its potential strength in about 7 days, according to Concrete Network; see concrete cure time.
What is a 1-2-3 concrete mix grade?
1-2-3 is a volume ratio (1 cement, 2 sand, 3 gravel), not a strength grade; strength depends on water and materials, so tested premix states its psi on the bag.
How long does 2 inches of concrete take to dry?
Thin concrete still needs 3 to 7 days of moist curing (NRMCA); see concrete curing time.
How thick should a concrete slab be?
At least 3½ in on the ground (2021 IRC R506.1); 4 in is standard for patios and car driveways.
Next step
Price the cement with the cement vs concrete, or skip the measuring with premix on the concrete bag calculator.
Official sources
Last reviewed 2026-11-05. Numbers come from our tested engine; see how we calculate and our sources.