A 10 × 10 ft slab is one of the most common DIY pours: a shed floor, a hot tub pad, a grill patio or a small landing. At the usual 4 inch thickness it takes 33.3 cubic feet (1.23 cubic yards) of concrete. That is 56 bags of 80 lb mix before waste, or 62 bags with 10% extra. This page answers that one question in detail and lets you change the thickness, bag size and waste, then tells you how much weight you'll be hauling and whether a ready-mix truck makes more sense.
For other shapes and sizes, the general concrete slab calculator handles any rectangle or circle. To convert a volume you already know into bags, use the concrete bags per yard calculator.
How to use the 10x10 concrete slab calculator
- Leave length and width at 10 ft, or change them if your pad is slightly different (a 10 × 12 shed, for example).
- Enter the thickness. 4 inches is typical for patios and sheds; hot tubs and small vehicles usually call for 5 to 6 inches. Measure the actual form depth, because the base is rarely perfectly flat.
- Keep 10% extra unless your base is laser-flat. Running short in the middle of a pour leaves a cold joint.
- Pick the bag size you plan to buy. The yield per bag comes from the manufacturer: 0.60 ft³ for 80 lb, 0.45 ft³ for 60 lb and 0.30 ft³ for 40 lb.
- Optionally enter your truck or trailer payload to see how many trips the bags take, and a bag price for the total.
Formula
Worked example
A 10 × 10 ft shed pad, 4 inches thick, 10% extra, 80 lb bags, hauled in a half-ton pickup rated for 1,500 lb.
- Volume: 10 × 10 × 4 ÷ 12 = 33.33 ft³ = 1.23 yd³.
- With 10%: 33.33 × 1.10 = 36.67 ft³ (1.36 yd³).
- Bags: 36.67 ÷ 0.60 = 61.1, so 62 bags of 80 lb (or 82 × 60 lb, or 123 × 40 lb).
- Weight: 62 × 80 = 4,960 lb, about 4 trips at 1,500 lb each, or one delivery.
At 4 inches, the slab weighs roughly 33.3 ft³ × 145–150 lb/ft³, close to 5,000 lb once cured, which is why small pads are often poured from a ready-mix short load instead.
10x10 slab concrete chart
Bags for a 10 × 10 ft slab at common thicknesses, with 10% extra. Bag yields are the manufacturer's published figures.
| Thickness | ft³ (exact) | yd³ with 10% | 80 lb bags | 60 lb bags | 40 lb bags | Weight of 80 lb bags (lb) |
|---|---|---|---|---|---|---|
| 3.5 in | 29.2 | 1.19 | 54 | 72 | 107 | 4,320 |
| 4 in | 33.3 | 1.36 | 62 | 82 | 123 | 4,960 |
| 5 in | 41.7 | 1.70 | 77 | 102 | 153 | 6,160 |
| 6 in | 50.0 | 2.04 | 92 | 123 | 184 | 7,360 |
A 5 inch slab uses 25% more concrete than a 4 inch slab; a 6 inch slab uses 50% more. A 3.5 inch slab, which is what a 2×4 form really gives you, uses about 12% less.
Bags or a ready-mix truck?
Above about 1 cubic yard, mixing by hand becomes a long day: 62 bags means 62 batches in a wheelbarrow, or around 20 to 30 batches in a rented drum mixer, and the first concrete placed must not set before the last arrives. Many ready-mix suppliers deliver small loads with a short-load fee, and some rent towable trailers that hold about 1 yard. Price both. For a 10 × 10 pad at 5 or 6 inches (1.5 to 1.7 yd³ with waste), a truck is usually less work and often similar in cost.
What goes under and inside a 10x10 slab
Most slabs sit on 4 inches of compacted gravel. For a 10 × 10 pad that is 1.23 yd³, or about 1.9 tons with 10% extra, which you can check in the gravel calculator. Reinforcement is optional for a light-use pad but common: a grid of #3 or #4 bar at 18 inches on center needs about 8 bars each way (16 in total); the rebar calculator works out the sticks. If the slab carries a wall or a heavy load at its edge, thicken the edge or add a footing (see the concrete footing calculator).
Caveats and assumptions
- Bag yields are for properly mixed concrete per the manufacturer. Too much water increases volume slightly but weakens the slab.
- Thickness varies when the base is uneven. Measure the form depth in several spots and use the average or the larger value.
- Local code or the product you are installing (hot tub, shed kit) may require a specific thickness, reinforcement or footing.
- Payload figures are your vehicle's rated capacity; never exceed it, and remember trailers have their own limits.
Frequently asked questions
How many 80 lb bags of concrete do I need for a 10x10 slab?
At 4 inches thick, 56 bags exactly, or 62 bags with 10% extra. At 6 inches, 84 exactly or 92 with 10% extra.
How many 60 lb bags of concrete for a 10x10 slab?
At 4 inches thick, a 10 × 10 slab needs 33.3 ft³ ÷ 0.45 = 74.1, so 75 bags with no extra, or 82 bags with 10% extra.
How many yards of concrete for a 10x10 slab?
1.23 cubic yards at 4 inches, 1.54 at 5 inches and 1.85 at 6 inches, before waste.
How thick should a 10x10 slab be?
Patios, walkways and shed floors are commonly 4 inches. Hot tubs, small garages or anything with wheels are often 5 to 6 inches. Follow your product's instructions and local code.
How much does a 10x10 slab weigh?
Concrete weighs roughly 145 to 150 lb per cubic foot, so a 4 inch 10 × 10 slab weighs about 4,800 to 5,000 lb.
Is it cheaper to use bags or ready-mix for a 10x10 slab?
It depends on local prices and short-load fees. For about 1.25 to 1.75 cubic yards, get a ready-mix quote and compare it with the bag total shown above; the truck also saves hours of mixing.
Sources
- Quikrete — Concrete Calculator and product yields — yield of 80, 60 and 40 lb bags
- Quikrete — Concrete Mix product information — mixing and placing bagged concrete
- Portland Cement Association — Concrete technology — concrete density and slab construction basics
- NIST — Unit Conversion — cubic feet to cubic yards
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.