Cement Calculator: Estimate Cement and Concrete Quantities
This cement calculator estimates the material you need and clarifies the difference between cement and finished concrete. Enter your dimensions to get volume in cubic yards plus the bag count for your slab, footing, or pour.
Estimated concrete
Estimates only. Add ~5–10% for waste. Bag yields: 40 lb ≈ 0.30, 60 lb ≈ 0.45, 80 lb ≈ 0.60 cu ft. Concrete ≈ 150 lb per cu ft.
How to Use the Cement Calculator
- 1
Enter your dimensions
Type the length, width and thickness of your slab, footing or pad and choose your units, feet, inches or meters.
- 2
Get instant volume
See the result in cubic yards, cubic feet and cubic meters, plus weight, the moment you type, no page reloads.
- 3
Buy the right amount
We convert volume into the exact number of 40, 60 and 80 lb bags, truck loads and cost so you order without waste or shortfalls.
The formula
Cement sacks = (Wet_ft³ × 1.54) ÷ total_parts ÷ 1 ft³/sack
- ·Wet_ft³ = finished concrete volume (ft³)
- ·1.54 = dry-to-wet bulking factor
- ·total_parts = cement + sand + gravel parts (e.g. 1+2+3 = 6)
- ·1 ft³/sack = volume of one 94 lb Portland sack
- ·water ≈ 5 gal per sack
Loose dry ingredients pack down when mixed with water, so multiply the finished volume by 1.54 to get dry volume. Split that by the mix ratio; the cement share divided by 1 ft³ gives the number of 94 lb sacks.
Worked examples
Example 1: One cubic yard of 1:2:3 concrete
- Wet volume = 27 ft³; dry = 27 × 1.54 = 41.58 ft³
- Total parts = 1 + 2 + 3 = 6
- Cement = 41.58 ÷ 6 = 6.93 ft³ → 7 sacks
- Water ≈ 5 × 7 = 35 gal
Result: About 7 sacks of 94 lb cement per yard
Example 2: 50 ft³ of 1:2:4 concrete
- Dry volume = 50 × 1.54 = 77 ft³
- Total parts = 1 + 2 + 4 = 7
- Cement = 77 ÷ 7 = 11 ft³ → 11 sacks
- Sand = 22 ft³, gravel = 44 ft³
Result: 11 sacks of 94 lb cement, 22 ft³ sand, 44 ft³ gravel
Concrete calculators by project type
Concrete bag yield & coverage
How much mixed concrete a standard bag yields, and how far a cubic yard goes at common slab depths.
| Bag size | Yield (cu ft) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 | 90 |
| 60 lb | 0.45 | 60 |
| 80 lb | 0.60 | 45 |
- 40 lb
- 60 lb
- 80 lb
Related guides
Cement Calculator FAQs
What is the difference between cement and concrete?
Cement is the powdered binder, usually portland cement, while concrete is the finished material made by mixing cement with sand, gravel, and water. You pour concrete, not pure cement.
How much cement is in a bag of concrete mix?
Bagged concrete mix already contains cement, sand, and aggregate, so you don't add cement separately. An 80 lb bag yields about 0.60 cubic feet of finished concrete.
How much cement do I need per cubic yard of concrete?
A typical concrete mix uses roughly 5 to 6 bags (94 lb each) of portland cement per cubic yard, depending on the target strength.
Can I use cement without sand or gravel?
Pure cement paste is weak and prone to cracking, so you need sand and gravel for strength; cement alone is only used for thin bonding or grout applications.
How many bags of concrete make a cubic yard?
It takes about 45 of the 80 lb bags, 60 of the 60 lb bags, or 90 of the 40 lb bags to make one cubic yard.
What type of cement is used in concrete?
Portland cement is the standard binder in most concrete, typically Type I or Type I/II for general residential work.
How many 94 lb sacks of cement are in a cubic yard of concrete?
For a standard 1:2:3 mix, a cubic yard (27 ft³) needs about 7 sacks of 94 lb Portland cement. The math is 27 × 1.54 ÷ 6 = 6.93 ft³ of cement, and each sack is roughly 1 ft³. Richer mixes with more cement per part raise that count.
How much does a bag of Portland cement weigh?
A standard sack of Portland cement in the US weighs 94 pounds and holds about 1 cubic foot of loose powder. In many other countries the standard bag is 50 kg. This calculator counts 94 lb sacks, so adjust if your bags are a different size.
Is Portland cement the same as concrete mix?
No. Portland cement is the gray binding powder; concrete mix is cement already blended with sand and gravel. Bagged concrete mix just needs water, while pure cement needs sand and aggregate added in the right ratio. Using cement alone without aggregate is weak and prone to cracking.
How much sand and gravel per bag of cement?
In a 1:2:3 mix, each 1 ft³ sack of cement pairs with about 2 ft³ of sand and 3 ft³ of gravel. So a 7-sack yard uses roughly 14 ft³ sand and 21 ft³ gravel before the 1.54 bulking is applied. Keep the ratio consistent for uniform strength.
How much water per sack of cement?
A common rule is about 5 gallons of water per 94 lb sack of cement, which gives a workable slump without weakening the paste. Adding more water thins the mix but drops the strength sharply. Aim for a plastic, moldable consistency rather than a soupy one.
Can I make concrete stronger by adding more cement?
Up to a point, yes; increasing the cement share (a lower ratio like 1:1.5:3) raises compressive strength. But too much cement increases shrinkage cracking and cost, so structural mixes are usually specified by target PSI instead. For most home projects a 1:2:3 mix hitting roughly 3,000 PSI is plenty.
How long does Portland cement last in storage?
Kept dry and sealed, cement stays usable for a few months, but it absorbs moisture from the air and slowly hardens. If the powder has lumps that will not crush between your fingers, it has partly hydrated and lost strength. Store bags off the floor on pallets and wrapped in plastic.