Concrete Curb Calculator
Estimate cubic yards, total weight, and 40/60/80-lb bag counts for curb-and-gutter sections in seconds. Preview linear runs in 3D and plan with less waste.
Curb-and-Gutter Formula, Linear Foot Takeoffs, and Bag Math
People searching concrete curb calculator usually need more than one raw volume number. They need the curb-and-gutter cross-section math, a reliable way to turn linear feet into cubic yards, realistic bag counts for short runs, and a sanity check on when the project should move to ready-mix instead.
Cross-section formula
This shape is not a plain rectangle. The tool calculates curb depth against the raised curb face, adds flag thickness under the curb, then adds gutter width times flag thickness to capture the flat section.
Linear feet to cubic yards
Once the curb-and-gutter section area is set, the calculator multiplies by total length and quantity, then converts the result from cubic feet to cubic yards so the estimate matches supplier language.
Bag logic used by this calculator
For small curb jobs, the same site math stays in play: about 0.3 ft³ per 40-lb bag, 0.45 ft³ per 60-lb bag, and 0.6 ft³ per 80-lb bag, rounded up so you do not come up short on pour day.
When curb runs stop being a bag job
A short patch, parking stop, or isolated curb repair may still work with bags. Once linear footage grows, waste percentage climbs, or multiple sections stack together, ready-mix usually becomes the more practical choice.