Concrete Curb & Gutter Calculator
Estimate concrete for a combined curb and gutter run from the cross-section dimensions and length — in cubic yards and bags.
How it works
cross-section (sq in) = curb height × curb width + gutter width × gutter thickness · cubic yards = (area ÷ 144) × length ÷ 27
A curb and gutter has a constant cross-section, so its volume is the cross-sectional area times the run length. The area is approximated as the curb block (its height times width) plus the gutter pan (its width times thickness). Dividing the area in square inches by 144 converts to square feet; multiplying by length and dividing by 27 gives cubic yards.
Worked example
An 18 in curb, 6 in wide, over an 18 in gutter pan 6 in thick: area = 18 × 6 + 18 × 6 = 216 sq in = 1.5 sq ft. Over 50 ft that is 75 cu ft ÷ 27 = 2.78 cubic yards — order about 3 yards of ready-mix.
Frequently asked questions
Does this include the batter and gutter slope?
No — it treats the section as simple rectangles, which slightly overestimates because real curbs have a sloped face and a dished pan. That small overage is fine for ordering, since you want to round up to the nearest quarter yard anyway.
Can I pour curb and gutter with bags?
Only for a very short repair section. A continuous run needs the consistency and working time of ready-mix so you can slip-form or hand-form and finish before it sets, so this is a truck job in practice.
How do I handle a long run?
Multiply the per-foot volume by the total footage. This calculator already does that — just enter the full run length, and add the standard 10% for spillage and form irregularities.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.