How much does an 80 lb bag of concrete cover?
An 80 lb bag of concrete mix makes about 0.6 cubic feet, which covers 1.8 square feet at 4 inches thick. At 2 inches it covers 3.6 square feet; at 6 inches, 1.2.
How to work it out
- One 80 lb bag makes 0.6 cu ft, so 27 cu ft per cu yd ÷ 0.6 cu ft = 45 bags per cubic yard
- 1 bags × 0.6 cu ft = 0.0222 cu yd
- Spread 4 in thick: 0.6 cu ft ÷ 0.333 ft = 1.8 sq ft
People are often surprised how little one bag goes: about a 16 × 16 in square at a normal slab thickness. That is the reason slab bag counts climb so fast.
Adjust for your project
More options: Thick
- Bags of this size per cubic yard
- 45 bags
- Yield of one bag
- ≈ 0.6 cu ft (17 L)
- Area covered at the thickness above
- 1.8 sq ft
- Weight of the bags
- 80 lb (0 tons)
- Full pallets (Quikrete pallet size)
- Less than a pallet (42 bags per pallet)
Area one bag covers, by thickness
| Pour thickness (for area covered) | Area covered at the thickness above | Concrete made |
|---|---|---|
| 2 in | 3.6 sq ft | 0.0222 cu yd |
| 3.5 in | 2.06 sq ft | 0.0222 cu yd |
| 4 in | 1.8 sq ft | 0.0222 cu yd |
| 5 in | 1.44 sq ft | 0.0222 cu yd |
| 6 in | 1.2 sq ft | 0.0222 cu yd |
One bag at different thicknesses
| Thickness | Area one 80 lb bag covers | Bags per 10 sq ft |
|---|---|---|
| 2 in | 3.6 sq ft | 2.8 |
| 3½ in (2×4 form) | 2.06 sq ft | 4.9 |
| 4 in | 1.8 sq ft | 5.6 |
| 5 in | 1.44 sq ft | 6.9 |
| 6 in | 1.2 sq ft | 8.3 |
Mixed with its 6–9 pints of water, an 80 lb bag weighs about 84 lb — 0.6 cu ft at the roughly 140 lb per cubic foot Quikrete gives for the fresh mix. It does not shrink noticeably in volume as it cures, so the 0.6 cubic feet is what ends up in the form.
Using the per-bag figure
For a quick count, divide your slab area by the coverage at your thickness: a 4 × 6 ft step landing 4 in thick is 24 ÷ 1.8 = 13.3 bags, so 14 plus a spare. For thin repairs under 2 in, a sand/topping mix or a resurfacer is the right product — see self-leveling concrete coverage per bag. Mixed weight per cubic foot is on how much does a cubic foot of concrete weigh. For a yard at a time, see how many 80 lb bags of concrete in a yard.
Different size? Use the full Concrete Bags per Yard Calculator.
What you’ll need
- Magnesium hand floatBudget price
Closes the surface and pushes stones down after screeding, and prepares the slab for a broom or trowel finish.
See options on Amazon (opens in a new tab) - Mortar and concrete mixing tubBudget price
A wide, shallow tub for one or two bags at a time — easier to clean and to pull a hoe through than a wheelbarrow.
See options on Amazon (opens in a new tab) - Concrete edger and groover setBudget price
The edger rounds slab edges so they don’t chip; the groover cuts control joints while the concrete is still soft.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How much does a 60 lb bag of concrete cover?
About 1.35 square feet at 4 inches thick, from its 0.45 cubic feet.
How much does a 40 lb bag of concrete cover?
About 0.9 square feet at 4 inches, or 1.8 square feet at 2 inches.
How much area do 10 bags of 80 lb concrete cover?
18 square feet at 4 inches thick (0.22 cubic yards).
Other common sizes
- How many 80 lb bags of concrete in a yard — 45 bags of 80 lb per cubic yard
- How many 60 lb bags of concrete in a yard — 60 bags of 60 lb per cubic yard
- How many bags of concrete on a pallet — 42 bags of 80 lb (56 of 60 lb, 80 of 40 lb), Quikrete
Sources
- Quikrete Concrete Mix (No. 1101) data sheet (opens in a new tab) — Yields: 40 lb ≈ 0.30, 50 lb ≈ 0.375, 60 lb ≈ 0.45, 80 lb ≈ 0.60, 90 lb ≈ 0.675 cu ft; unit weight ≈ 140 lb/cu ft; for pours 2 in thick or more; 6–9 pints of water per 80 lb bag; control joints every 6–8 ft; cure 5 days at 70 °F or above, 7 days at 50–70 °F; protect from freezing for 48 hours.
- Quikrete Fast-Setting Concrete Mix (No. 1004) data sheet (opens in a new tab) — 50 lb ≈ 0.375 cu ft, 60 lb ≈ 0.45 cu ft, 25 kg ≈ 11.6 L, 30 kg ≈ 14 L; sets in 20–40 minutes; post holes 3× the post width and ⅓ of the post length deep; wait 4 hours before loading a post.
- Quikrete 5000 Concrete Mix (No. 1007) data sheet (opens in a new tab) — 60 lb ≈ 0.45, 80 lb ≈ 0.60 cu ft; ≈ 140 lb/cu ft; 1,500 psi at 1 day, 2,500 at 3, 3,500 at 7 and 5,000 at 28 days; 2 in minimum thickness.
- Sakrete High-Strength Concrete Mix technical data sheet (opens in a new tab) — Yields: 40 lb 0.30, 60 lb 0.45, 80 lb 0.6, 90 lb 0.66 cu ft; 25 kg 0.41, 30 kg 0.50 cu ft.
- Quikrete Concrete Mix (No. 1101) — product page with pallet quantities (opens in a new tab) — 40 lb bags 80 per pallet; 60 lb bags 56 per pallet; 80 lb bags 42 per pallet.
- NIST Handbook 44, Appendix C — General Tables of Units of Measurement (opens in a new tab) — 1 cubic yard = 27 cubic feet; 1 cubic foot = 1,728 cubic inches.