Concrete Cost Calculator
Enter the slab dimensions and your two local prices. It works out the cheaper route — bagged mix or delivered ready-mix — and shows both totals side by side.
How the cost is calculated
- Volume = length × width × thickness (inches ÷ 12), then ÷ 27 for cubic yards.
- Bag route = cubic feet ÷ bag yield (0.60 cu ft for 80 lb), rounded up, × your price per bag.
- Ready-mix route = cubic yards × your delivered price per yard.
- The cheaper of the two becomes the headline number. Both are shown underneath.
Worked example
A 10 ft × 12 ft slab at 4 inches, mix at $6 per 80 lb bag and ready-mix at $150 per yard:
- 40 cu ft, plus 5% = 42 cu ft = 1.56 cu yd
- Bags: 42 ÷ 0.60 = 70 bags × $6 = $420
- Ready-mix: 1.56 × $150 = $234
Ready-mix wins by nearly $200 — but only if you can take a full truck. Below about half a yard, the short-load fee eats that advantage and bags are the cheaper, simpler choice.
Typical US prices
| Item | Typical range | Notes |
|---|---|---|
| 80 lb bag of mix | $5–7 | Higher in city centres and small hardware stores |
| Ready-mix, per cubic yard | $130–180 | Delivered, before fees |
| Short-load fee | $50–150 | Charged under 3 yards by most suppliers |
| Saturday / early delivery | $50–200 | Varies by plant |
| Finished slab, installed | $12–20 per sq ft | Includes forms, pouring and finishing |
Frequently asked questions
How much does a yard of concrete cost?
Ready-mix runs about $130–180 per cubic yard delivered. Bagged mix is far more expensive per yard — an 80 lb bag yields 0.60 cu ft, so it takes 45 bags to make a yard, which is $250–350 at typical bag prices.
How much does a 10x10 slab cost?
At 4 inches thick the slab is 1.23 cubic yards. That is 59 bags of 80 lb mix — roughly $350 — or about $190–230 delivered as ready-mix before the short-load fee.
Is it cheaper to mix your own?
Only for very small pours. Under half a yard, bags avoid the delivery minimum. Above one yard, ready-mix is cheaper per yard and saves hours of mixing — the labour is the real cost, not the powder.
Why is my quote higher than this?
Most quotes include the gravel base, rebar, formwork and finishing labour. This calculator prices the concrete itself. Ask the contractor to break the quote into material, base prep and labour so you can compare line by line.