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Number of pavers, bedding sand, and material cost for a rectangular patio by paver size, with a waste allowance.
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Concrete Edging Calculator
Bags of concrete mix for a curb or flat edging run, from linear feet, profile size and coverage per bag.
Concrete Edging Calculator
Chlorova · updated for 2026
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Coverage figures are typical yields for an 80-pound bag of concrete mix poured to the named profile on level ground, and real output moves with subgrade dips, form leaks, how wet the mix is and how straight your trench holds. High curbs generally need reinforcement, a proper form board and expansion joints against cracking, none of which is priced here, and the bag cost ignores forms, rebar, tools and your labor. Round up rather than down, because a missing bag leaves a cold joint in the line, and re-check the yield stated on the specific product you buy before ordering in volume.
A concrete curb is the one landscape edge that outlives every plastic strip and steel roll, and it is mixed and poured by the bag rather than by the cubic yard, which makes the shopping list a simple division problem. This concrete edging calculator turns the length of your run and the profile you want into the bags of mix to order, the total pounds of concrete that represents, and a rough material bill. Pick flat grade beam or a curb height, enter the feet, and the pallet count is settled before you dig the trench.
Ordering Curb Concrete in Steps
- Choose the edging profile, since height drives coverage per bag.
- Measure the full linear feet of edge you intend to pour.
- Enter the current shelf price of an 80 lb bag of concrete mix.
- Set a waste allowance for trench dips and form leaks.
- Read the bare bag math first to see the ideal coverage.
- Buy the rounded-up bag count, never the fractional one.
- Use total pounds to plan trips, a mixer or a wheelbarrow.
- Note the cold-joint warning before committing to a long unbroken run.
How Bag Counts Are Worked Out
Each profile carries a coverage rate in linear feet per eighty-pound bag, the number the picker supplies: about a hundred feet for a flat grade beam, falling to roughly thirty-seven for a deep curb, because the taller the section the more concrete each foot demands. Dividing your run length by that rate gives the bare bag count, which is exactly why doubling curb height nearly doubles material.
The buying figure adds a waste percentage for trench irregularity and mixing losses, then rounds up with a ceiling, since hardware stores do not sell a seventh of a bag and one short bag leaves an ugly cold joint at the end of the run. Total pounds are simply bags times eighty, the figure that tells you whether to rent a mixer, and the cost multiplies those same rounded bags by your entered price. Any zero length returns nothing, as it should.
Worked Example: Sixty Feet of Standard Curb
- You are edging a walk with sixty feet of two by four curb.
- That profile covers 75 linear feet per 80 lb bag.
- Bare math says 60 divided by 75, which is 0.8 bags.
- Adding a ten percent waste allowance nudges it to about 0.88 of a bag.
- Rounded up, you buy a single bag for the whole sixty-foot run.
- That is 80 pounds of concrete mix in the cart total.
- At six dollars a bag the material costs just 6 dollars.
- Switch to the deep curb and the count climbs toward two bags.
- Two spare bags cost twelve dollars, cheap insurance against a cold joint.
Coverage per 80 lb Bag
Typical linear-foot yields by curb profile for one 80-pound bag of mix, the rates the profile picker applies. Trench depth consistency and how stiff your form boards are shift these a foot or two either way on any real pour.
| Profile | Section (in) | Lin ft per bag |
|---|---|---|
| Flat grade beam | 4 wide x 2 deep | 90-110 |
| Standard curb | 2 x 4 | 65-85 |
| Tall curb | 2 x 6 | 45-55 |
| Deep curb | 2 x 8 | 32-42 |
| Bullnose edge | 3 x 4 | 55-65 |
Key Terms
- Grade beam
- A shallow flat concrete band that separates lawn from bed at ground level.
- Curb
- An above-ground concrete edge, usually two to eight inches tall, that holds soil back.
- Cold joint
- The weak seam where fresh concrete meets set concrete, often from running short on bags.
- Form board
- The temporary wood wall that holds wet curb to shape until it cures.
- Expansion joint
- A planned gap every so many feet that lets a long curb crack there, not randomly.
Notes from People Who Pour Edges
- The trench is the hidden variable, because a grade that wanders two inches low over twenty feet quietly eats another bag, and pros dig to a constant bottom rather than a constant top.
- Buy ten percent over the ceiling rather than trusting it, since patching a cold joint weeks later costs more than the two spare bags sitting in the garage would have.
- Height is expensive in non-linear ways, as a deep curb needs rebar or mesh and stouter forms, and those consumables can rival the concrete itself in the receipt.
- A smooth finish comes from working in cool damp hours, not from the mix recipe, so pour early in morning and keep a bone-dry hot afternoon off the schedule.
- Long straight runs crack where you want them to only if you cut joints, so tool or saw them every few feet while setting rather than letting nature choose the line.
Common Mistakes & Fixes
- Ordering the fractional bag count and finishing the run with a wet seam at the end.
- Measuring the diagonal of curves instead of walking the actual centerline with tape.
- Pouring deep curbs dry without mesh, then enjoying the hairline cracks by autumn.
- Ignoring the waste allowance on rocky, uneven subgrade that swallows extra mix.
- Mixing thin for easier flow, which weakens the curb far more than it speeds work.
- Skipping expansion joints on long runs and letting the curb pick its own crack line.
When to Use This (and When Not To)
Use it for straight-to-gently-curved perimeter pours where bag yield is the real shopping question, from walk edges to bed boundaries. It prices concrete only, so size a paver field with the patio-paver calculator, count lumber for a timber edge with the raised-bed-lumber tool, and skip the pour entirely for a simple steel or plastic border measured by the linear foot.
Concrete Edging Calculator: Frequently Asked Questions
How many bags of concrete for a curb?
Divide the linear feet by the coverage rate for your profile, roughly 75 feet per 80-pound bag for a standard two-by-four curb, then round up with waste. A sixty-foot run is therefore a single bag, while the same length in a deep curb takes about two.
How far does an 80 lb bag of concrete go?
Near a hundred feet as a flat grade beam, sixty-five to eighty-five as a standard curb, and down to the thirties for an eight-inch curb, because every added inch of height adds concrete to each foot. Trench consistency decides which end of those ranges you actually land on.
Is concrete edging better than plastic or steel?
For permanence yes, since a poured curb outlives every flexible strip and can be repaired in sections, while plastic bends to any curve cheaply and steel holds a razor line but costs real money per foot. Choose concrete where edges will be hit by mowers for decades.
Do I need reinforcement in a concrete edge?
Under four inches tall, rarely, as the mass and the trench do the holding, but taller curbs and anything retaining a sloped bed want fiber or mesh because freeze-thaw will find the plain concrete first. Rebar is overkill for a curb and useful for a wall.
How much does concrete edging cost?
Material for a standard curb runs only a few dollars per foot in bags alone, which is why the calculator shows sixty feet at about six dollars, and forms, labor and any deep-curb reinforcement multiply that several times. Get the bag count right first, then price the crew.
Can I pour curb concrete without a mixer?
Yes, in a wheelbarrow or directly on a tarp with a hoe, which is how most short residential edges actually get mixed. One bag is about two and a half 50-pound sacks of premix, so hand mixing stays reasonable right up to roughly the ten-bag mark.
Sources & Further Reading
- Concrete Driveways, Curbs and Walks — American Concrete Association. Basis for coverage yields, jointing and reinforcement guidance on this page.
- Mixing and Placing Small Concrete Projects — University of Illinois Extension. Underpins the waste allowance and cold-joint recommendations here.
- Landscape Edging Options Compared — Penn State Extension. Source of the concrete versus flexible edging trade-off notes.
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