Concrete Curb Calculator
Installing landscape edging or street curbs? Enter your dimensions to find out how much concrete you need, whether you're ordering ready-mix or using bags.
Why Curbs Matter
Curbs define edges and control drainage. In landscaping, they separate grass from gravel or mulch and prevent soil erosion. On streets, they channel runoff to storm drains and protect sidewalks from vehicle encroachment.
A well-built curb holds its shape for decades. The key is a solid base. Compact the subgrade and add 4 inches of gravel before setting forms. This prevents the curb from settling unevenly and cracking along its length.
Proper reinforcement matters too. Even a small curb benefits from one piece of #3 or #4 rebar running continuously through it. The steel resists tension forces from soil expansion and freeze-thaw cycles that would otherwise crack plain concrete.
Forming and Pouring
Set forms straight and level using a string line and stakes every 3 to 4 feet. Curbs stand out when they're crooked or wavy. Take your time aligning the forms before mixing any concrete.
Use a stiff mix with low slump. Curbs are vertical, so runny concrete sags before it sets. A 3- to 4-inch slump holds its shape better and produces a denser, more durable curb. Add fiber reinforcement to the mix for extra crack resistance.
Finish the top with a steel trowel for a smooth surface that sheds water. Round the edges slightly with an edger to prevent chipping. Strip the forms after 12 to 24 hours and moist-cure the curb for at least 3 days by covering it with wet burlap or plastic.
Common Curb Applications
Landscape curbs create clean borders around flower beds, trees, and driveways. They keep mulch in place and reduce trimming along edges. Paint or stain them to match your hardscape for a cohesive look.
Parking curbs (wheel stops) protect buildings, fences, and landscaping from vehicles. Standard wheel stops are 6 to 8 inches tall and 8 to 10 inches wide, poured or precast in sections anchored to the pavement.
Monolithic curbs are poured at the same time as a driveway or parking lot slab. This eliminates the joint between the curb and pavement, creating a stronger, more durable edge that resists separation over time.
Frequently Asked Questions
What is the standard size for a concrete curb?
Residential curbs are typically 6 inches tall and 6 inches wide. Parking lots and streets often use 6-inch by 8-inch or larger curbs for vehicle barriers.
Do I need rebar in a curb?
Rebar or wire mesh helps curbs resist cracking from soil movement and vehicle impacts. Most contractors install at least one piece of #4 rebar centered in the curb.
Can I pour curbs in sections?
Yes, but use construction joints every 10 to 20 feet to control cracking. Dowel the sections together if the curb serves as a vehicle barrier.
What mix strength should I use?
A 3,000 to 4,000 psi mix is standard for curbs. Higher strengths resist impact better but cost more and can be harder to finish.
How do I form a curb?
Use plywood or metal forms held in place with stakes. Coat the forms with release agent so they come off cleanly. Check for level and alignment before pouring.