Concrete calculator: yards and cost
A cubic yard of ready-mix costs $155 to $235 delivered in 2026, and one yard covers 81 square feet at 4 inches thick. This calculator turns slab dimensions into yards of concrete, yards of gravel base, square feet of wire mesh, and a full cost range with finishing labor at $3.75 to $7.50 per square foot. Change the thickness and every number updates.
Worked example: 20 ft slab length, 20 ft slab width, 4 in thickness
That takes 4.9 cubic yards (Concrete needed). National-average costs:
| Line | Quantity | Cost range |
|---|---|---|
| Ready-mix concrete | 4.94 cubic yards | $766 to $1,161 |
| Gravel base, 4 inches | 4.94 cubic yards | $183 to $287 |
| Wire mesh reinforcement | 400 sq ft | $124 to $192 |
| Finishing labor | 400 sq ft | $1,500 to $3,000 |
| Form lumber, stakes, expansion joint, cure and seal | 8% | $86 to $131 |
| Estimated total | $2,658 to $4,771 |
Enter slab length, width and thickness and the yardage and cost update as you type. The interactive calculator on this page recomputes these numbers for your dimensions and adjusts for any US state.
How to measure for concrete work
Measure the footprint
Tape the length and width at the longest points. For an L shape or a slab that wraps a corner, split it into rectangles, figure each one, and add them together. Do not eyeball it off the plans if you can walk the site.
Pick the thickness by use
4 inches for patios and sidewalks, 5 to 6 for driveways, 6 or more for anything that carries equipment. Thickness is the input clients forget to mention and the one that moves the yardage fastest on big footprints.
Convert to yards
Length times width times thickness in inches, divided by 324, gives cubic yards. A 600 square foot driveway at 5 inches is 9.3 yards. Round up to the quarter yard when you call the plant.
Check the grade before you quote
Measure the fall across the site with a string line or laser. More than a few inches of cut or fill means extra base, taller forms, or a grading charge that the per-foot price does not cover.
What this calculator assumes
- Prices are national averages for a straightforward broom-finish slab on grade.
- The total includes ready-mix, 4 inches of compacted gravel base, wire mesh, and finishing labor.
- The 8 percent allowance covers form lumber, stakes, expansion joint, and cure and seal.
- Tear-out of existing concrete, major grading, pump truck fees, and permits are not included.
- Pours under about 4 yards usually carry a short-load fee from the ready-mix plant.
- Decorative work prices differently: stamped and colored flatwork sells for roughly double a broom finish.
Cost factors in concrete work
Thickness and mix strength
Every extra inch of depth is 25 percent more concrete on a 4 inch baseline, and stepping up from 3,000 to 4,000 psi or adding fiber costs more per yard. Driveways and equipment pads sit at the expensive end of both.
Access and pumping
If the truck can back up to the forms, you pour straight off the chute. A backyard slab behind a fence means wheelbarrows and burned hours, or a line pump that adds several hundred dollars to the pour.
Finish type
Broom finish is the baseline this calculator prices. Stamped and decorative concrete sells for $14 to $25 per square foot installed against $7 to $13 for plain flatwork, because color, stamping and sealing roughly double the labor.
Tear-out and grading
Demoing an existing slab or driveway adds $2 to $4 per square foot before the first form stake goes in. A site that needs real cut and fill adds base material and machine time on top.
Weather and season
Cold weather means heated water, accelerators and blankets. Hot weather means retarders and a bigger finishing crew working faster. Both push cost up, and spring backlogs push lead times out.
Frequently asked questions
How many yards of concrete do I need for a 20x20 slab?
A 20 by 20 slab at 4 inches thick takes 4.9 cubic yards. The math is length times width times thickness in inches, divided by 324. Order about a quarter yard extra so a slightly low spot in the grade does not leave the pour short with the truck already gone.
How thick should a concrete slab be?
Patios and sidewalks are fine at 4 inches. Driveways should be 5 to 6 inches, and anything carrying trucks or equipment, like an RV pad or shop floor, wants 6 inches or more. Going from 4 to 6 inches adds 50 percent more concrete, so thickness is the first thing to pin down with the client.
What does a yard of concrete cost in 2026?
Ready-mix runs $155 to $235 per cubic yard delivered as a national average, with 3,000 psi at the low end and 4,000 psi and admixtures pushing higher. Most plants also charge a short-load fee on pours under about 4 yards, which is why small pads cost more per foot than big ones.
Does the calculator include rebar?
It prices welded wire mesh at $0.31 to $0.48 per square foot, which is standard for patios and walks. Driveways often spec #4 rebar on 18 inch centers instead, which runs $0.82 to $1.30 per linear foot of bar. Swap the mesh line for rebar when the job calls for it.
What does Staxen cost for concrete contractors?
Staxen is $59 per month per AI employee, or $149 per month for all three. Eddie the Estimator turns a spoken slab description into a priced, line-item estimate the client can sign from a texted link, deposit included. Your first job is free, no card required.
Start free with Staxen: your first job is on us, no card required.