PROJECT SUMMARY
Concrete Slab project summary
Volume1.63 cu yd
- Pour
- Slab
- Dimensions
- 12 × 10 ft × 4" thick
- Supply
- 74 × 80 lb bags
- 60 lb bags
- ≈ 98
- Cubic feet
- 44 cu ft
- Difficulty
- Intermediate
- Build time
- 1–1.5 days
- Estimated materials
- $599–$810
Concrete Slab, Footing & Column Calculator
Cubic yards, bags or ready-mix for a slab, footing or column pour.
Configure
Concrete Slab calculator
What are you pouring?
Thickness
Advanced optionsfine-tune the details…
Estimates are planning aids, not a professional quote. Double-check quantities and product coverage — and any local code or permit requirements — before you buy.
⚠ Always order a little extra (the overage above) — you can't go back for 'a bit more' once a pour starts without leaving a cold joint.
Cost breakdown
Material only · national-average rates
| Concrete & Footings | $486–$658 |
| Soil & Fill | $50–$68 |
| Lumber & Decking | $42–$56 |
| Fasteners & Hardware | $21–$28 |
| Total | $599–$810 |
Excludes tools, delivery, tax and permit fees. Labor not included — this is a DIY materials estimate.
Shopping list
Every item · grouped by store sectionThese are affiliate links: we may earn a commission if you buy through them, at no extra cost to you. It never changes what the calculator recommends — the shopping list comes from your dimensions, not from what pays.
Lumber & Decking
- 7× 8 ftEdge forms — 2×4
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Concrete & Footings
- 74× bagsConcrete — 80 lb bags — 12 × 10 ft × 4" thick · 1.63 cu yd
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- 6× 42×84 sheetWelded wire mesh (6×6)
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Fasteners & Hardware
- 22× eaForm stakes
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Soil & Fill
- 1.48× cu ydGravel base (3/4" minus) — 4" compacted
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Tools
✓ required · ○ helpful
- Wheelbarrow & shovel
- Screed board (straight 2×4)
- Concrete float & edger
- Margin / finishing trowel
- Mixing tub or mixer (rental) — bagged mixing
- Tape measure & level
- Rubber boots & gloves
Project notes
- Estimates are a planning aid. Concrete volume is length × width × thickness in feet; the overage covers spillage, uneven subgrade and slightly over-filled forms — it's normal to run a touch over.
- An 80 lb bag of mixed concrete yields about 0.60 cubic feet, a 60 lb bag about 0.45, and a 40 lb bag about 0.30. Above roughly two cubic yards, ready-mix delivery is the practical and usually cheaper choice.
- Build solid, braced forms and a compacted base before you pour. Concrete is heavy and unforgiving — a blown form or soft spot mid-pour is hard to recover from.
- Keep the finished concrete damp for several days while it cures; it gains most of its strength curing wet, not drying out. Tool control joints into slabs so cracks form where you want them.
About this calculator
How to estimate a concrete slab
Enter your dimensions and the Concrete Calculator returns the exact volume — in cubic yards and cubic feet — plus how many 80, 60 or 40 lb bags it takes, or when to switch to ready-mix delivery. It handles the three shapes you actually pour: a flat slab, a strip footing, and round columns or post piers.
For slabs it also sizes the gravel base, wire mesh or rebar grid, and edge forms. Pick the shape, type in the size, and the takeoff updates instantly so you can order the right amount the first time — running short mid-pour is the one mistake you can't undo.
Step by step
How to pour a concrete slab
A step-by-step walkthrough to go with your plan above. Follow the product instructions and any local code or permit requirements as you work.
- 1
Measure and pick the shape
Decide whether you're pouring a slab, a strip footing, or round columns, and measure the dimensions in the same units. The calculator above turns them into cubic yards and a bag count with an overage built in.
- 2
Excavate and compact the base
Dig to your subgrade, add and compact a gravel base for slabs, and dampen it before the pour. A firm, level base is what keeps concrete from cracking and settling.
- 3
Build and brace the forms
Set straight, well-staked 2× forms to your finished height with any drainage slope built in. Concrete pushes hard — over-brace rather than under-brace.
- 4
Place reinforcement
Lay wire mesh or a rebar grid on chairs so it sits in the middle of the slab thickness, and set any column or footing rebar to your plan.
- 5
Pour and screed
Place the concrete, working from the far end, and screed it flush to the form tops by sawing a straight board across them. Fill low spots as you go.
- 6
Float, edge and joint
Once the surface sheen leaves, bull-float or hand-float it, run the edger around the perimeter, and tool control joints into slabs at a sensible spacing.
- 7
Finish and cure
Trowel smooth or broom for grip, then keep it damp with a cover or curing compound for several days. Don't load it heavily until it has cured.
Equip the job
Recommended gear for this build
Hand-picked categories that match the shopping list above. Links open a current selection so you can compare brands and prices.
These are affiliate links: we may earn a commission if you buy through them, at no extra cost to you. It never changes what the calculator recommends — the shopping list comes from your dimensions, not from what pays.
Concrete & FootingsHigh-strength concrete mix (80 lb)The standard bagged mix for slabs, footings and setting posts.
$6–9/bag
Concrete & FootingsWelded wire mesh / rebarHolds cracks tight and keeps a slab from shifting — set it on chairs in the middle.
$9–15
ToolsMagnesium float & edgerLevels the surface and rounds the edges so they don't chip.
$30–70
ToolsConcrete mixer (rental)Worth renting once you're mixing more than a dozen bags by hand.
$40–70/day
Finishing & SealantConcrete curing compoundLocks moisture in so the slab cures to full strength instead of drying out.
$25–45
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Answers
Frequently asked questions
How do I calculate how much concrete I need?
Multiply length × width × thickness, all in feet, to get cubic feet, then divide by 27 to get cubic yards. A 12×10 slab at 4 inches thick is 40 cubic feet, or about 1.5 cubic yards. For footings and round columns the shapes differ, so this calculator does the geometry for each and adds an overage so you don't come up short.
How many bags of concrete are in a yard?
A cubic yard is 27 cubic feet. An 80 lb bag yields about 0.60 cubic feet, so it takes about 45 of them per yard; 60 lb bags yield about 0.45 cubic feet (about 60 per yard) and 40 lb bags about 0.30 (about 90 per yard). The calculator shows the 80, 60 and 40 lb counts so you can compare against what your store stocks.
When should I order ready-mix instead of bags?
Roughly two cubic yards is the tipping point. Below that, mixing bags is manageable; above it, the bag count and mixing time get punishing and ready-mix delivery is faster, stronger from the consistent mix, and usually cheaper. The calculator flags when you've crossed into ready-mix territory and switches the takeoff to cubic yards.
How thick should a concrete slab be?
Four inches over a compacted gravel base handles patios, sheds and walkways. Go to 5–6 inches with rebar for driveways, heavy equipment, or poor soils. Whatever the thickness, keep reinforcement suspended in the middle of the slab and tool control joints in so the inevitable shrinkage cracks form where you want them.