Concrete Curb Calculator
This concrete curb calculator works out the concrete for a straight curb, or a curb and gutter section, from its cross-section and length. Enter the curb height and width, the gutter width and thickness if there is one, the length, and a waste allowance, and the concrete curb calculator returns the volume in cubic yards, cubic meters, and cubic feet, plus the concrete per 100 feet.
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The Concrete Curb Calculator is part of our Concrete collection. Browse more concrete to size, convert, and check your work alongside this tool.
What the concrete curb calculator does
A curb is a long, narrow pour, so its volume is the cross-section area times the length. A plain curb is roughly a rectangle; a curb and gutter adds a flat gutter flag in front of the curb. The concrete curb calculator adds the two areas, converts square inches to square feet, multiplies by the length, and adds waste for uneven subgrade and spillage.
Concrete curb calculator formula
Real curb faces are often sloped or have a rounded top, which removes a little concrete; the rectangle method errs slightly high, which acts as a safety margin.
Concrete curb and gutter example
100 ft of curb and gutter: a 6 in wide curb 18 in high, with a 24 in gutter 6 in thick, and 10% waste:
That is 5.45 m³. Without waste the section takes 6.48 yd³ per 100 ft, a handy figure for longer runs.
How to use the concrete calculator for curb and gutter
Enter the total curb length in feet. Enter the curb height from the bottom to the top, not just the part above the road, and the curb width. For a curb and gutter, enter the gutter width in front of the curb and its thickness; set the gutter width to zero for a curb only. Keep about 10% waste and press Calculate.
Reading your curb concrete volume
Order ready-mix by the cubic yard, rounded up to the next quarter or half yard. Curb and gutter is usually slip-formed or poured in forms with a stiff mix, so the truck schedule matters as much as the volume. For short landscape curbs, bagged concrete can work, but past about a yard ready-mix is cheaper and more consistent.
When to use a curb and gutter calculator
- Pricing curb and gutter for a road or parking lot
- Ordering concrete for a driveway curb
- Estimating landscape edging curbs
- Checking a bid quantity
- Planning truck loads for a long run
Common concrete curb calculator mistakes
- Using only the exposed height. Enter the full height down to the base.
- Counting the curb width twice. Gutter width is the part in front of the curb.
- Mixing inches and feet. Section in inches, length in feet.
- No waste allowance. Subgrade is never perfectly even.
Tips for concrete curbing
- Add expansion joints about every 10 ft.
- Compact the base before forming.
- Order a stiffer mix for slip-formed curbs.
Curb and gutter volume for common sections
Road agencies publish standard sections, and most residential curb and gutter falls between 5 and 8 cubic yards per 100 feet. A barrier curb with a vertical face holds more concrete than a mountable or rolled curb of the same width. For the slab or sidewalk behind the curb, switch to the concrete calculator, which works from length, width, and thickness.
Concrete calculator for curb: bags or ready-mix
An 80 lb bag yields about 0.6 cubic feet, so even 20 feet of a 6 x 12 in landscape curb takes about 17 bags. The concrete bag calculator gives the exact count for small runs. For bids and budgets, the concrete slab cost calculator turns volume into a material and labor estimate you can adjust for curb work.
Concrete curb calculator chart: yards per 100 ft
| Section | Cross-section | Concrete per 100 ft (no waste) |
|---|---|---|
| 6 x 12 in curb only | 72 in² | 1.85 yd³ |
| 6 x 18 in curb only | 108 in² | 2.78 yd³ |
| 6 x 18 in curb + 12 x 6 in gutter | 180 in² | 4.63 yd³ |
| 6 x 18 in curb + 24 x 6 in gutter | 252 in² | 6.48 yd³ |
| 8 x 24 in curb + 24 x 8 in gutter | 384 in² | 9.88 yd³ |
Concrete Curb Calculator FAQ
How do you calculate concrete for a curb?
Multiply the cross-section area in square feet by the length, then divide by 27 for cubic yards. A 6 x 18 in curb is 0.75 ft², so 100 ft takes 2.78 yd³.
How much concrete for curb and gutter?
A 6 x 18 in curb with a 24 x 6 in gutter takes about 6.5 yd³ per 100 ft before waste.
What is the concrete curb calculator formula?
Volume = (curb height × width + gutter width × thickness) ÷ 144 × length, in cubic feet.
How much waste should I add?
About 5 to 10% for formed curbs, more on uneven subgrade.