Concrete Curb and Gutter Calculator
This curb and gutter calculator builds the cross-section from its parts, the curb block plus the gutter pan plus an optional fillet triangle, then multiplies that area by the length of the run. It returns the cross-sectional area in square feet, cubic yards per 100 linear feet, total cubic yards, bag counts, and an installed cost by the linear foot.
How to use this calculator
- Pull the dimensions off your local standard drawing first. Public work is built to a state DOT or city section such as CG-6 or a Type A, and the inspector signs off against that drawing, not against an estimate.
- Enter the curb height above the pan, which is the exposed face height, and the curb width across the top of the block.
- Enter the gutter pan width from the face of the curb out to the pavement edge. Twenty four inches is the workhorse width; 18 inches is common on residential streets.
- Enter the section thickness, meaning how deep the pan sits. Six to eight inches is typical, usually matching the pavement next to it.
- Add a fillet only if your section drawing shows a triangular haunch where the curb face meets the pan. Leave both fillet boxes blank when the section is a plain curb sitting on a flat pan.
- Enter the run length, keep a 10 percent waste allowance, and read the cubic yards per 100 feet from the result panel.
The formula
Break the section into simple shapes, add up the areas, then run that cross-section down the length of the job:
Cross-section ft² = (Curb height ft × Curb width ft) + (Pan width ft × Thickness ft) + (0.5 × Fillet base ft × Fillet height ft)
Cubic yards = Cross-section ft² × Length ft ÷ 27
The fillet term is half the base times the height because a haunch is a triangle. Leave it out and the two rectangles are all you need.
Worked example. A standard section with a 24 inch pan 6 inches thick and a 6 inch by 6 inch curb standing on top of it. In square inches the pan is 24 × 6 = 144 and the curb is 6 × 6 = 36, so the section is 180 square inches. Divide by 144 and the cross-section is 1.25 square feet. Over a 100 foot run that is 125 cubic feet, or 125 ÷ 27 = 4.63 cubic yards. Add 10 percent and you would order 5 yards.
Estimators think in yards per 100 linear feet because that number travels well: once you know a section takes 4.63 yards per 100 feet, an 850 foot job is roughly 39 yards without touching the geometry again. The calculator prints that rate for you.
Pouring a plain curb with no gutter pan? Use the concrete curb calculator, which drops the pan out of the section entirely. For the steps on site, see how to pour a concrete curb.
Frequently asked questions
How much concrete do I need for curb and gutter?
Find the cross-sectional area in square feet, multiply by the run length, then divide by 27. A standard 1.25 square foot section needs about 4.6 cubic yards per 100 linear feet.
What is the standard size of curb and gutter?
A common section is a 6 inch curb on a gutter pan 18 to 24 inches wide, with the section 6 to 8 inches thick. Your state DOT standard drawing sets the exact geometry.
What is the fillet field for?
The fillet is the small triangle of concrete where the curb face meets the gutter pan. Leave both fillet fields at zero for a square section, or enter the base and height to include it.
How much does curb and gutter cost per linear foot?
Installed curb and gutter runs about $8 to $24 per linear foot. The cost estimate above prices labor per linear foot, which is how curb work is actually quoted.
Why does the calculator show a cross-sectional area?
Because curb work is estimated per 100 linear feet. Once you know the cross-section in square feet, any run length is a single multiplication.