Concrete Slab Calculator
Get material quantities, cubic yardage, rebar estimates, and cost ranges for any concrete slab project.
Concrete Slab Calculator
// Slab Estimate
Concrete Slab Thickness Guide
Choosing the right slab thickness is as important as calculating the volume. Too thin and the slab cracks under load; too thick and you're wasting money on material and extending cure time unnecessarily.
| Application | Thickness | Rebar? | PSI Rating |
|---|---|---|---|
| Garden path / walkway | 3–4" | Optional | 3,000+ |
| Patio | 4" | Wire mesh recommended | 3,000+ |
| Residential driveway | 4–5" | #3 rebar or mesh | 4,000+ |
| Garage floor | 5–6" | #4 rebar | 4,000+ |
| RV / heavy vehicle pad | 6" | #4 rebar grid | 4,000+ |
| Foundation slab | 6–8" | #4–#5 rebar | 3,000–4,000 |
Do You Need Rebar or Wire Mesh?
Wire mesh (welded wire reinforcement) is commonly used in residential patio and walkway slabs to help control cracking. It's inexpensive and easy to install. Rebar provides stronger structural reinforcement and is recommended for driveways, garage floors, and any slab subject to heavy loads or frost-heave conditions.
For most DIY patios and walkways, 6×6 W1.4×W1.4 welded wire mesh is the standard specification. Position it on chairs or small rocks to keep it at the mid-depth of the slab — ideally in the lower third — not flat on the ground.
Concrete Slab Cost Breakdown
The material cost from the calculator above covers only the concrete itself. A complete slab project involves several additional costs that homeowners frequently underestimate.
Site preparation — grading, compacting the base, and adding gravel — typically adds $1-$2 per square foot. Form lumber (the wood framing that holds the concrete in place) runs $0.50-$1.50 per linear foot of perimeter. Reinforcement (rebar or mesh) adds $0.50-$1.50 per square foot. Finishing, stamping, or sealing adds $1-$5 per square foot depending on complexity.
Professional installation all-in typically runs $6-$12 per square foot for a standard decorative finish, or $4-$7 per square foot for a basic broom finish. A DIY pour can reduce the labor portion to near zero, but requires renting a mixer, buying or renting screeds and floats, and having 2-4 helpers available on pour day.
Frequently Asked Questions
- How thick should a concrete slab be?4 inches for patios and walkways; 4-6 inches for driveways; 5-6 inches for garage floors; 6-8 inches for structural foundations. Check local building codes for your specific project.
- How much does a concrete slab cost per square foot?Materials only (concrete): roughly $2-$4 per square foot. Professionally installed with forming, finishing, and cleanup: $5-$12 per square foot depending on thickness, finish, and region.
- How long does a concrete slab take to cure?Initial set is 24-48 hours (foot traffic okay). 7-day cure allows most normal loads. Full 28-day cure is required before parking heavy vehicles or applying structural loads. Keep the slab moist during the first 7 days to prevent cracking.
- Should I pour my own slab or hire a contractor?Small slabs under 100 sq ft are DIY-friendly. Anything larger moves quickly once the truck arrives — you typically have 90 minutes to place, screed, and finish before the concrete becomes unworkable. Hire a contractor for anything over 200 sq ft unless you have concrete experience and 3-4 helpers lined up.