Calculators / Driveways
Concrete driveway calculator
Put in the length, width and thickness. You’ll get the yards of ready-mix, the tons of base gravel and where the control joints go.
Updated · How we check our numbers
Order about
6.75 cubic yards
For a 40 × 12 ft driveway, 4 in thick, with 10% extra. Under it, 4 in of compacted gravel: about 11 tons.
- Area
- 480 sq ft
- Concrete
- 6.75 yd
- Gravel base
- 11 tons4 in compacted
- Panels
- 106 × 8 ft
Estimate for planning only, not professional advice. Check the manufacturer’s instructions, your local code and a licensed professional before you buy, build or install. Use at your own risk. Terms.
concrete = 480 sq ft × 4 in ÷ 12 ÷ 27 × 1.1 = 6.52 yd, rounded up to the quarter yard
base = 480 × 4 in ÷ 12 ÷ 27 × 1.85 t/yd = 11 tons
joint spacing = 30 × 4 in ÷ 12 = 10 ft; panels no longer than 1.5 × their width
Cut joints at most 10 ft apart (NRMCA: 24 to 36 times the thickness, never over 15 ft): 1 down the length, making 2 lanes 6 ft wide, and 4 across, every 8 ft. Cut them 1 in deep (a quarter of the slab), within 4 to 12 hours of finishing.
Ask for 4000 psi with 6% air (for ¾ or 1 in stone), NRMCA’s mix for slabs that freeze and see salt. Skip deicers the first winter, and never use ammonium or magnesium-based ones.
Keep it wet or covered for 3 to 7 days (NRMCA), and keep cars off for at least 3 days (ACI 330R). Trucks and heavier, 7 days.
Wire mesh won’t stop cracks; NRMCA says it keeps them tight. The joints are what control where it cracks. Some cities require mesh or fibers anyway.
The apron in the city’s right-of-way usually has its own spec and permit, often 6 in thick.
How we work it out
yards = sq ft × inches ÷ 12 ÷ 27 × 1.1, rounded up to the quarter yard
Thickness: the cities we read ask for 4 in over 4 in of compacted gravel (Shaker Heights, OH; Des Plaines, IL) up to 6 in (Davison, MI), and 6 in for the apron in the street right-of-way. ACI's residential concrete standard is behind a paywall, so we haven't used it.
Joints: NRMCA puts them 24 to 36 times the slab's thickness apart, about 10 ft for 4 in, and never more than 15 ft, with panels no longer than 1½ times their width. We use 30 times. The mix is NRMCA's: 4000 psi and 6% air where it freezes and sees salt.
Where the numbers come from
- NRMCA CIP 6: joints in concrete slabs on grade
- NRMCA CIP 2: scaling of concrete surfaces (mix, deicers)
- NRMCA CIP 11: curing in-place concrete
- FHWA, quoting ACI 330R on opening to traffic
- Shaker Heights, OH: asphalt and concrete driveway requirements
- Davison, MI: driveway standards
- Des Plaines, IL: driveway permit guide
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