How much concrete for a 10×12 shed?
Order 1.63 cubic yards for a 10 × 12 ft shed slab 4 inches thick: 1.48 cubic yards in the forms plus 10% extra. That is about 74 bags of 80 lb mix. With a thickened edge, plan on about 2 cubic yards.
How to work it out
- 12 ft × 10 ft = 120 sq ft
- 120 sq ft × 4 in ÷ 12 = 40 cu ft ÷ 27 = 1.48 cu yd
- + 10% extra = 1.63 cu yd = 44 cu ft
- 44 cu ft ÷ 0.6 cu ft per 80 lb bag = 74 bags
A 10×12 is the most popular backyard shed size, and a concrete floor gives it a base that won’t rot or shift. The slab itself is modest; what changes the order is whether the edges are thickened.
Adjust for your project
More options: Extra · Price
- Or bags of mix (incl. extra)
- 74 bags · 80 lb bag
- Concrete before the extra
- 1.48 cu yd (40 cu ft)
- Slab area
- 120 sq ft
- Weight of the concrete (≈ 145 lb/cu ft)
- 5,800 lb (3 tons)
- 74 bags is a lot of mixing. Compare a ready-mix delivery (ask about minimum loads and short-load fees) with the bags vs ready-mix calculator.
- Total to buy counts this as ready-mix. Switch “How will you buy it?” to bags if you are mixing it yourself.
- Plan control joints about 1 in deep every 6–8 ft (Quikrete’s guidance) so shrinkage cracks follow your lines.
10×12 shed slab by thickness (10% extra included)
| Thickness | Concrete to order | Or bags of mix (incl. extra) | Weight of the concrete (≈ 145 lb/cu ft) |
|---|---|---|---|
| 3.5 in | 1.43 cu yd | 65 bags | 5,075 lb |
| 4 in | 1.63 cu yd | 74 bags | 5,800 lb |
| 5 in | 2.04 cu yd | 92 bags | 7,250 lb |
| 6 in | 2.44 cu yd | 110 bags | 8,700 lb |
Flat slab vs thickened edge
A plain 4 in slab for a 10 × 12 shed is 1.48 yards, 1.63 with the extra. Many shed slabs are poured with the edge turned down — deeper around the perimeter so the walls sit on more concrete. Whether yours needs one, and how deep, depends on the shed, your soil and your local rules, so check with your building department; some areas treat larger sheds as structures with foundation requirements.
If you do thicken the edge, add it separately: the perimeter of a 10 × 12 is 44 ft. An edge 8 in wide and 4 in deeper than the slab adds 44 × 0.67 × 0.33 = 9.8 cu ft, about 0.36 yards, or 17 more of the 80 lb bags. The footing volume calculator handles that with your real dimensions.
Bags or truck for a shed floor
Seventy-four bags is a long day even with a mixer, and the slab has to be placed in one go. With a thickened edge the total is about 2 yards (1.63 + 0.36), so many people order 2 yards of ready-mix for a shed this size. Set anchor bolts or straps into the wet concrete if the shed is to be fastened down; mark their positions on the forms first. For reinforcement, many shed slabs get welded wire mesh or a fiber mix — check the shed maker’s foundation guide and your building department; the steel itself is counted on how much wire mesh for a slab. The base under the slab is worked through on how much gravel under a concrete slab, and a smaller shed pad on how many bags of concrete for an 8×8 slab. If you would rather sit the shed on a low block wall, see how many cinder blocks for a 10×10 shed.
Different size? Use the full Concrete Calculator.
What you’ll need
- Aluminum screedMid-range price
A straight, light screed strikes off the concrete level with the forms. A straight 2×4 works too if it really is straight.
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) - Hand tamperBudget price
Compacts gravel base in small areas and post holes. For a full slab base, rent a plate compactor.
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 concrete for a 10×12 shed slab 6 inches thick?
2.22 cubic yards before extra, 2.44 cubic yards with 10%.
How much concrete for an 8×10 shed base?
1.09 cubic yards at 4 inches with 10% extra, or 49 bags of 80 lb.
How much concrete for a 10×10 shed?
1.36 cubic yards with 10% extra at 4 inches (62 bags of 80 lb), before any thickened edge.
Other common sizes
- How much concrete for a 10×10 slab — 1.36 cu yd with 10% extra (62 bags of 80 lb)
- How much concrete for a 12×12 slab — 1.96 cu yd with 10% extra (order 2 yd)
- How much concrete for a 20×20 slab — 5.43 cu yd with 10% extra at 4 in
- How many yards of concrete for a 24×24 slab — 7.82 cu yd with 10% extra at 4 in
- How much concrete for a 30×40 slab — 16.3 cu yd with 10% extra at 4 in
- How many bags of concrete for a 4×4 slab — 10 bags of 80 lb (14 of 60 lb), 4 in thick
- How many bags of concrete for an 8×8 slab — 40 bags of 80 lb, 4 in thick
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.
- NRMCA Concrete in Practice 31 — Ordering Ready Mixed Concrete (opens in a new tab) — Truck mixers carry 8 to 12 cubic yards (about 6 to 9 m³); order 4–10% more than the plan estimate; a loaded truck weighs about 80,000 lb; fresh concrete can cause severe chemical burns.
- NRMCA Concrete in Practice 2 — Scaling Concrete Surfaces (opens in a new tab) — Order air-entrained concrete (about 6% air) for exterior slabs exposed to freezing and de-icers; avoid de-icing chemicals in the first winter.
- Iowa DOT Instructional Memorandum 340 — Weight per cubic foot, yield and air content of concrete (opens in a new tab) — Normal-weight concrete is typically 140–150 lb per cu ft at 5 to 8 percent air.
- OSHA 3351 — Preventing Skin Problems from Working with Portland Cement (opens in a new tab) — Wet portland cement can cause caustic burns that may not hurt at first and in severe cases reach the bone.
- 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.