How to use it
- Enter the curb's length in feet
- Enter the width in feet
- Enter the thickness in inches
- Click Calculate to see cubic yards, bags, and cubic feet
This concrete curb calculator tells you exactly how much concrete to order before you mix a single bag. Enter the curb's length, width, and thickness, and you'll instantly get three numbers: cubic feet (the raw volume), cubic yards (what ready-mix trucks use), and 80-lb bags (what you'll buy at the store). Each 80-lb bag yields about 0.6 cubic feet, so the bag count is based on that constant. Why does this matter? Ordering too little means a cold joint or a second mix that doesn't match. Ordering too much wastes money and creates disposal headaches. Use the cubic yards figure if you're having concrete delivered; use the bag count if you're mixing by hand or with a small mixer. For example, a 10 ft by 1 ft by 4 in curb needs about 3.3 cubic feet — that's roughly 6 bags. The calculator does this in seconds, so you can plan accurately and confidently.
Pro tips
- Add 10% waste for spillage, uneven subgrade, or over-excavation — round bag counts up to the next full bag
- For small jobs under 20 bags, buy extra and return unopened bags; for large jobs, order ready-mix to avoid mix consistency issues
- Measure thickness at the curb's thinnest point, not the form height, to avoid under-ordering
- Double-check that length and width are in feet and thickness in inches — mixing units is the #1 cause of miscalculation
Real-life examples
- A homeowner pouring a new driveway curb and wanting to know how many bags to haul from the store
- A landscaper estimating concrete for a garden border curb spanning 50 feet
- A contractor quoting a parking lot island curb and needing cubic yards for a ready-mix order
Case study
Before, Maria guessed at concrete amounts for her front walkway curb and ended up with 3 extra bags and a trip back to the store. After using this calculator, she entered her 12 ft by 1.5 ft by 4 in dimensions, saw she needed 8.9 cubic feet (about 15 bags), bought 17 with waste, and finished in one afternoon.