How to use the concrete slab cost calculator
- Enter the slab. Type the length, width and thickness of the slab, or its area and thickness.
- Enter your prices. Choose how your price is quoted: per cubic yard, per square foot or per bag. Type the price, then add a delivery fee, a labour rate per square foot or other costs if you have them.
- Read the cost. The result shows the total cost, a breakdown and the cost per square foot, next to the cubic yards and the bags.
What is a concrete slab cost calculator?
A concrete slab cost calculator is a tool that estimates what a slab will cost. It finds the volume of concrete in the slab, multiplies it by a price, and adds the other costs you enter.
This calculator uses only your prices. It has no built-in price for concrete, delivery or labour, because those prices change from one town and one supplier to the next. Get a quote, type it in, and the maths is done for you.
Features
- A price per cubic yard, per square foot or per bag
- Separate fields for a delivery fee, labour per square foot and other costs
- The total cost, a cost breakdown and the cost per square foot
- A slab from length and width, from area and thickness, or a round slab
- The cubic yards to order and the bag counts next to the cost
- An adjustable waste allowance
- A live 3D preview, a PDF of the estimate and a WhatsApp share button
What you can use it for
- Pricing a patio, a shed base or a garage slab
- Comparing a contractor's price per square foot with your own numbers
- Adding delivery and labour to the cost of the concrete
- Working out the cost per square foot of a quote
How the slab cost is calculated
| Your price is | Concrete cost |
|---|---|
| Per cubic yard | Cubic yards to order × price per cubic yard |
| Per bag | Number of bags of the chosen size × price per bag |
| Per square foot | Area of the slab × price per square foot |
Total cost = concrete cost + delivery fee + (labour per square foot × area) + other costs.
Cost per square foot = total cost ÷ area of the slab.
The cubic yards to order include the waste allowance. A price per square foot is treated as a quote for the finished area, so waste is not added to it and the labour field is hidden.
Worked example with example prices
The prices below are made-up numbers to show the maths. They are not market prices. Replace them with your own quote.
- Slab: 20 ft × 10 ft × 4 in = 66.67 cubic feet = 2.47 cubic yards. With 10% waste: 2.72 cubic yards. Area: 200 square feet.
- Concrete at an example $150 per cubic yard: 2.72 × 150 = $407.41.
- Delivery fee, example $60: $60.00.
- Labour at an example $3 per square foot: 3 × 200 = $600.00.
- Total: 407.41 + 60 + 600 = $1,067.41.
- Cost per square foot: 1,067.41 ÷ 200 = $5.34.
The calculator multiplies the unrounded 2.716 cubic yards by the price, which is why the concrete cost is $407.41 and not $408.00.
What a slab quote can include
A slab costs more than its concrete. When you compare quotes, check which of these each quote covers. The calculator gives you a field for each, or you can add them together in other costs.
- The concrete itself, priced per cubic yard or per bag
- A delivery fee, and any charge for a small load
- Labour to form, pour and finish the slab
- Site work: digging, grading and a gravel base
- Reinforcement such as rebar or wire mesh
- Forms, a pump, permits and removal of old concrete
What the calculator includes
- The calculator does not add tax.
- The slab has one thickness. Thickened edges and footings are not included.
- Labour is entered per square foot of slab. If your labour is quoted another way, put the amount in other costs.
- Each dimension can be up to 10,000 in its unit, an area up to 1,000,000 and each price or cost up to 1,000,000. Waste can be 0 to 50%.
- Bag counts use the yields in the Quikrete Concrete Mix data sheet (product 1101, revised October 2022).
Is it private?
Yes. The calculation and the PDF are made in your browser. The sizes and prices you type are not sent to our server and are not saved.
Tips for an accurate estimate
- Get the price per yard or per bag in writing from your supplier and enter that exact figure.
- Ask whether the quote includes delivery, fuel and short-load charges, and add them if it does not.
- Price the same slab with bags and with ready-mix to see which is cheaper for your size.
- Keep the waste allowance in the cost, because you pay for the concrete you order, not the concrete you place.
- Save the PDF with the price and the date, so you can compare quotes later.
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Frequently asked questions
- How much does a concrete slab cost?
- It depends on the size of the slab and on local prices for concrete and labour. Ask a local supplier or contractor for a quote, then enter the price here to get the total and the cost per square foot.
- How do I calculate the cost of a concrete slab?
- Find the cubic yards: length × width × thickness in feet, divided by 27, plus waste. Multiply by the price per cubic yard. Then add delivery, labour and any other costs.
- How do I work out the cost per square foot of a slab?
- Divide the total cost by the area of the slab. For a 200 square foot slab with a total cost of $1,067.41, the cost is $5.34 per square foot.
- Should I enter a price per cubic yard or per square foot?
- Enter the price the way it was quoted. Ready-mix suppliers usually quote per cubic yard. Contractors often quote a finished slab per square foot, which already includes labour.
- Does the cost include delivery and labour?
- Only if you enter them. The calculator has a field for a delivery fee, a field for labour per square foot and a field for other costs. Empty fields count as zero.
- Why does the calculator not show a price for concrete?
- Concrete prices change by place, by supplier and over time, and a wrong price would give a wrong total. The calculator uses only the prices you enter.
Sources
Every figure this calculator uses comes from the published sources below. The formulas are on this page, so any result can be checked by hand.
- Quikrete, Concrete Mix No. 1101: data sheet and product page. Bag yields: 0.30 ft³ (40 lb), 0.375 ft³ (50 lb), 0.45 ft³ (60 lb) and 0.60 ft³ (80 lb); bags per pallet: 80, 56 and 42.
- Federal Highway Administration (FHWA), Report FHWA-HRT-05-057. Normal-weight concrete: 145 lb per cubic foot (1.96 tons per cubic yard).