Curb and Gutter Calculator
A curb and gutter calculator multiplies run length by cross-section area, then ÷ 27. 200 ft of a 1.5 sq ft profile is 300 ft³, or 11.11 cubic yards of concrete.
How much concrete is in a curb and gutter run?
A curb and gutter calculator multiplies the length of the run by the area of the profile’s cross-section. Volume in cubic feet = length × cross-section area, and cubic yards = that ÷ 27. A 200 ft run of a profile with a 1.5 sq ft cross-section is 300 cubic feet, or 11.11 cubic yards.
Curb and gutter keeps the same shape for its whole length, whether it is slipformed by a machine or poured into hand-set forms. Once you know the area of one slice, the rest is multiplication.
The formula in plain words
Imagine slicing the curb across, like a loaf of bread. Every slice is the same shape. The area of that slice, in square feet, times the length of the loaf, in feet, gives the volume.
- Cross-section area in square feet, from the standard detail or worked out from its dimensions.
- Cubic feet = run length × cross-section area.
- Cubic yards = cubic feet ÷ 27.
Worked examples
- 200 ft run at 1.5 sq ft (calculator defaults)
- Volume: 200 × 1.5 = 300 ft³
- Cubic yards: 300 ÷ 27 = 11.11 yd³
- With a 10% buffer you would order about 12.22 yd³
- 150 ft run, profile worked out from a drawing
This example profile has a 6 in wide curb back standing 18 in tall, plus a 24 in wide gutter pan 7 in thick in front of it. Your standard detail will differ.
- Curb back: 0.5 ft × 1.5 ft = 0.75 sq ft
- Gutter pan: 2 ft × (7 ÷ 12) ft = 1.17 sq ft
- Cross-section: 0.75 + 1.17 = 1.92 sq ft
- Enter 150 ft and 1.92 sq ft: 150 × 1.92 = 288 ft³, or 10.67 yd³
The gutter pan holds more concrete than the curb itself.
Concrete per 100 ft by cross-section
| Cross-section area | Ft³ per 100 ft | Yd³ per 100 ft |
|---|---|---|
| 1.00 sq ft | 100 | 3.70 |
| 1.25 sq ft | 125 | 4.63 |
| 1.50 sq ft | 150 | 5.56 |
| 1.75 sq ft | 175 | 6.48 |
| 2.00 sq ft | 200 | 7.41 |
Scale by your length. A 640 ft run at 1.5 sq ft is 6.4 × 5.56 = 35.6 yd³, which is several ready-mix trucks and worth scheduling as staggered loads.
How to measure a curb and gutter run
- Length: measure along the face of the curb. On curves, measure along the curb line itself, not a straight chord across it.
- Radius returns at corners: measure the arc length. For a quarter circle, that is about 1.57 × the radius.
- Cross-section: take dimensions from the standard detail. Use the full depth of concrete, including anything below the gutter flow line.
- Driveway cuts and ramps: lowered sections at driveways and curb ramps often use a smaller profile. Measure those lengths separately and run them with their own area.
- Inlets and catch basins: deduct their length, since they are separate structures.
Common mistakes
- Using the default 1.5 sq ft without checking. It may be off by a third either way.
- Mixing inches and feet in the area. A 6 × 18 in rectangle is 0.75 sq ft, not 108. Convert each dimension to feet first, or divide square inches by 144.
- Forgetting the base. Most details call for compacted aggregate under the curb. That is a separate material.
- Ordering the net volume. Subgrade high and low spots change the real thickness of the pan.
Related concrete tools
For a curb without a gutter pan, the concrete curb calculator works from height and width. A walk behind the curb is calculated with the concrete sidewalk calculator, and bars or dowels can be counted with the rebar calculator. Public curb and gutter must follow the local agency’s standard detail and inspection process, so confirm the profile with the agency or the project’s civil engineer before ordering.
Frequently asked questions
What cross-section area should I use for a standard curb-and-gutter run?
Use the area from your project's standard detail. The 1.5 sq ft default is only a starting figure for a combined curb and gutter. Larger profiles with a wide gutter pan and tall curb face can approach 2 sq ft or more, and small rolled curbs can be well under 1.5.
How do I work out the cross-section area from a drawing?
Split the profile into rectangles and triangles, find each area in square feet, and add them. For example, a 6 in × 18 in curb back (0.5 × 1.5 = 0.75 sq ft) next to a 24 in × 7 in gutter pan (2 × 0.583 = 1.17 sq ft) totals about 1.92 sq ft.
Why does curb-and-gutter cross-section area vary so much?
Each city or state publishes its own details. Vertical (barrier) curb, rolled curb, and mountable curb have different face heights and shapes, and gutter pans range in width. A change from 1.5 to 2 sq ft adds a third more concrete over the whole run.
Does this calculator account for waste or overpour?
No. It returns the net volume. Ready-mix is usually ordered with a buffer for grade changes, form flex, and spillage; adding 10% turns 11.11 yd³ into 12.22 yd³. Ask your supplier or crew what buffer they use on slipformed versus hand-formed work.
Where do I find the exact cross-section area for my profile?
The municipal or state standard detail drawing for that curb type lists every dimension, and some list the area or the cubic yards per 100 ft directly. On private work, the civil drawings or the contractor's submittal should show the profile.
Estimates only. Verify quantities with your supplier before purchasing.