Concrete Curb Calculator
This concrete curb calculator works out how much concrete a curb needs from three numbers: the height, the width, and the length of the run. It returns cubic yards, cubic feet, weight, and 40/60/80 lb bag counts, and it will price the job by the linear foot. Use it for street curb, a driveway edge, a mow strip, or decorative landscape curbing.
How to use this calculator
- Measure the length of the run along the face of the curb and enter it. Measure curves along the arc, not across the chord, or you will come up short.
- Enter the curb height in inches. Street curb is usually 6 inches above the gutter line, landscape curbing sits around 4 to 6 inches, and a mow strip is nearly flush.
- Enter the curb width in inches, measured across the top of the section. Six inches is the common width for residential work.
- If you are pouring several separate runs at the same profile, set the number of runs and the calculator multiplies for you.
- Leave the waste allowance at 10 percent. A curb is a narrow ribbon, so spillage, an uneven trench bottom, and the concrete left in the chute cost you proportionally more than they would on a slab.
The result panel shows the cross-sectional area and the cubic yards per 100 linear feet, which is the number to quote when you call the ready-mix plant.
The formula
A curb is a linear shape, so you do not calculate it like a slab. Find the area of one cross-section, then push that cross-section along the length of the run:
Cubic yards = (Height ft × Width ft) × Length ft ÷ 27
Because the height and width are usually given in inches, divide each by 12 before multiplying, or work in square inches and divide the cross-section by 144 to get square feet.
Worked example. A 6 inch tall by 6 inch wide curb running 100 feet. Six inches is 0.5 ft, so the cross-section is 0.5 × 0.5 = 0.25 square feet. Multiply by the 100 foot run and you get 25 cubic feet, which is 25 ÷ 27 = 0.93 cubic yards. Add 10 percent for waste and you would order about 1 cubic yard, or mix roughly 42 bags of 80 lb concrete.
This calculator treats the cross-section as a rectangle. A real curb with a battered face, a chamfered top, or a rolled profile holds slightly less concrete than the rectangle around it, so the estimate runs a little high. That is the safe direction to be wrong in: coming up half a yard short in the middle of a pour leaves a cold joint you cannot hide.
Pouring a gutter pan along with the curb? The pan adds a large flat area to the section, so use the concrete curb and gutter calculator instead. If you want the background first, the concrete curb guide covers types, costs, and how the pour goes.
Frequently asked questions
How much concrete do I need for a curb?
Multiply the curb height by the width in feet to get the cross-section, multiply by the run length, then divide by 27. A 6 by 6 inch curb running 100 feet needs about 0.93 cubic yards.
How wide is a standard concrete curb?
Most residential and landscape curbs are about 6 inches wide and 6 inches tall. Garden borders and mow strips can be as narrow as 4 to 5 inches.
Does this calculator work for a rolled or angled curb?
Yes, with a small margin. It treats the section as a rectangle, so an angled or roll-top curb comes out slightly high. That is the safe direction for ordering concrete.
How much does a concrete curb cost per linear foot?
Installed landscape curbing runs about $6 to $14 per linear foot. Open the cost estimate above to price your own run with editable material and labor rates.
How many bags of concrete for a curb?
A 6 by 6 inch curb 100 feet long is about 0.93 cubic yards, or roughly 42 eighty-pound bags. Bag mixing is practical up to about a cubic yard; order ready-mix above that.