Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
This tool runs in your browser. Your calculator inputs and results are never transmitted to us or to ad/affiliate partners. Ads and sponsored links may set third-party cookies to serve and measure them, but they never receive your calculation values. If you explicitly save a scenario, its permitted fields stay in local browser storage until you clear them. See our Privacy Policy.
Use this result
Share the current inputs or ask ChatGPT to explain the calculation in context.
What does this calculator estimate?
A concrete cost calculator estimates the price of a slab by area. Enter the area, the rate per square foot, thickness, and waste to get the total estimated cost.
- Cost = area × rate × (1 + waste)
- Rate bundles material, labor, and finish
- Thickness affects the rate
How slab costs are estimated
Concrete contractors commonly price slabs per square foot, with the rate reflecting thickness, finish, reinforcement, and local labor. The estimate multiplies that rate by the area and adds waste.
Limitations to watch for
The rate you enter is the biggest variable — it changes by region, thickness, finish (broom vs stamped), and site access. The estimate excludes excavation, sub-base, and permits. Actual bids vary widely; treat this as a planning range, not a quote.
How to use it in practice
Get local per-square-foot rates for your region and thickness. Add 10% waste for spillage and over-excavation. Compare 2–3 contractor bids against this estimate to spot outliers.
['Enter the slab area in square feet.', 'Enter the local rate per square foot.', 'Enter the thickness and waste %; the tool computes total cost.']
How this calculator works
Formula
Total slab cost = area × rate per sq ft × (1 + waste%). The rate per square foot bundles material, labor, and finishing for the selected thickness.
Worked example
A 400 sq ft slab at $8.00/sq ft with 10% waste: 400 × 8 × 1.10 = $3,520 estimated cost.
Assumptions to verify
- The rate per square foot is user-entered from local pricing.
- Waste covers spillage and over-excavation.
- Excavation, sub-base, and permits are not included.
Frequently asked questions
How much does a concrete slab cost per square foot?
It varies widely by region, thickness, and finish — commonly in the $4–$12/sq ft range for material, labor, and finishing. Enter your local rate for a planning estimate.
What's included in the rate?
Typically material, labor, forming, and a standard broom finish. Stamped, colored, or reinforced work costs more.
Why add waste?
Slabs often need a little more concrete than the nominal volume — uneven grade, spilled concrete, and over-dig. 10% is a safe buffer.
Does this include excavation?
No. Site prep, sub-base gravel, and permits are usually quoted separately.
How do I get an accurate rate?
Ask 2–3 local contractors for per-square-foot pricing on a slab of your thickness and finish, then compare against this estimate.
Is a thicker slab always better?
No — thicker costs more. 4 in is standard for patios and sidewalks; driveways often use 5–6 in. Match the thickness to the load.
Can I DIY it cheaper?
Sometimes, for small slabs — but you carry the labor and risk. Ready-mix minimums and finishing skill matter. Use this to compare DIY vs contractor costs.
Cite this tool
BoringToolsKit. “Concrete Cost Per Square Foot Calculator.” boringtoolskit.com/concrete-cost-per-square-foot/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Any future sponsored recommendation or advertisement will be clearly labeled and kept separate from the calculation.