Concrete Curb Calculator
Calculate cubic yards of concrete for a curb run from its length, width, and height, plus material cost at your price per yard.
How this calculator works
Curbing is a long, narrow concrete form — essentially a thin rectangular strip run along a property line, driveway, or parking area. This calculator treats it the same way as any rectangular pour: total run as length, curb width as width, and curb height as depth, converted to cubic yards.
Formula: Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27.
Worked example
A 50 ft curb run, 6 inches (0.5 ft) wide, at a 6-inch depth:
- Depth in feet: 6 ÷ 12 = 0.5 ft
- Cubic yards: (50 × 0.5 × 0.5) ÷ 27 ≈ 0.46 yd³
- At $150/yd³, that’s $69.44 before waste.
Cost reference
| Curb run | Width | Cubic yards | Cost at $150/yd³ |
|---|---|---|---|
| 25 ft | 0.25 ft | 0.12 yd³ | $18.06 |
| 50 ft | 0.5 ft | 0.46 yd³ | $69.44 |
| 100 ft | 1 ft | 1.85 yd³ | $277.78 |
How to measure your curb
Walk the planned curb line and total every straight and curved section’s length in feet, then measure the curb’s width at its base and its height (depth) from the reference grade it sits on. For decorative landscape curbing with a rounded profile rather than a flat rectangular top, this calculator’s rectangular estimate runs slightly high — a safe direction to be off in, since a small surplus is easier to deal with than running short mid-pour.
Frequently asked questions
What do the fields mean for a curb, since curbs aren't flat slabs?
Length is the total curb run, width is the curb's width at its base (6 inches, or 0.5 ft, is a common landscape curb width), and depth is the curb's height. This treats the curb as a simple rectangular cross-section, which slightly overestimates a curb with a rounded or profiled top but is close enough for ordering purposes.
What's the difference between formed and extruded curbing?
Formed curbing is poured into wooden or metal forms set up along the run, the same way a footing or slab is poured — this calculator's rectangular volume estimate applies directly. Extruded (slip-formed) curbing is pushed through a machine that shapes it continuously, often with a profiled top rather than a flat rectangle, so actual concrete use can run slightly less than this estimate depending on the profile.
How wide should a curb be?
Decorative landscape curbing is often 4-6 inches wide, while structural driveway or parking-lot curbs are commonly 6-8 inches wide with a taller reveal above grade. Check your local code or landscape plan for the specified width — curb sizing for anything load-bearing (parking areas, streets) is a code-driven decision, not a style choice.
Do I need rebar in a curb?
Small decorative landscape curbs usually don't require reinforcement, but structural curbs along driveways or parking areas — especially ones tied into a slab or gutter system — often call for rebar per local code. This calculator estimates concrete volume only.
Should I add extra concrete for a curb pour?
Yes — narrow curb forms are prone to minor over-dig and spillage along the run, so the standard 10% waste allowance is a reasonable buffer. Running short partway through a continuous curb run is harder to patch cleanly than most other pour shapes, so err toward ordering slightly more.
Estimates only. Verify quantities with your supplier before purchasing.