Concrete Sidewalk Calculator
Enter your walkway’s length, width and thickness — across one or more sections — to get bags, cubic yards, cost and a score joint layout.
Sidewalk dimensions
A walkway that turns a corner is often easier to enter as separate straight sections.
Sets a thickness of 4 in — adjust below if needed.
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Bags or ready-mix?
Bags are the right call
Score joint planner
Mixing & weight
The short answer
Multiply total length × width × thickness, all in feet, then divide by 27 for cubic yards. A 50 ft long, 4 ft wide sidewalk at 4 inches thick needs about 0.62 cubic yards — roughly 28 bags of 80 lb concrete mix. If your walkway bends, add each straight section’s length together before multiplying by the width.
Concrete needed for common sidewalk lengths
Figures below use a 4 ft width and 4 inch thickness, before waste.
| Length | Area (4 ft wide) | Cubic yards | 80 lb bags |
|---|---|---|---|
| 25 ft | 100 sq ft | 0.31 yd³ | 14 |
| 50 ft | 200 sq ft | 0.62 yd³ | 28 |
| 75 ft | 300 sq ft | 0.93 yd³ | 42 |
| 100 ft | 400 sq ft | 1.23 yd³ | 56 |
| 150 ft | 600 sq ft | 1.85 yd³ | 84 |
Sidewalk width and thickness guide
| Use | Typical width | Typical thickness |
|---|---|---|
| Single-file garden path | 2–3 ft | 3–4 in |
| Standard residential walkway | 4 ft | 4 in |
| Accessible / two-person path | 5 ft | 4 in |
| Public sidewalk | 5–6 ft | 4–5 in |
| Driveway apron / vehicle crossover | Matches driveway | 6 in |
How to calculate concrete for a sidewalk
- Measure every section. Add up the length of each straight run if the path bends.
- Choose width and thickness. 4 ft wide and 4 inches thick is standard for residential use.
- Find the volume. Total length × width × thickness (converted to feet) gives cubic feet.
- Convert to cubic yards. Divide by 27.
- Add waste. 5–10% covers spillage and uneven sub-base.
Worked example
A walkway with a 50 ft front section and a 15 ft side section, both 4 ft wide, 4 inches thick:
- Total length50 + 15 = 65 ft
- Area65 × 4 = 260 sq ft
- Thickness in feet4 ÷ 12 = 0.333 ft
- Volume260 × 0.333 = 86.7 cu ft
- Cubic yards86.7 ÷ 27 = 3.21 yd³
- Plus 10% waste3.53 yd³
Past roughly half a cubic yard, ready-mix usually becomes more practical than mixing over 150 bags by hand.
Score joints vs expansion joints
A score joint is a shallow groove, cut or formed, that controls where the slab cracks within a continuous pour. The standard rule of thumb is to space score joints roughly equal to the sidewalk’s width, keeping each panel close to square — a 4 ft wide sidewalk typically gets a score joint every 4 to 5 feet.
An expansion joint is different: a full-depth gap, often filled with flexible material, placed wherever the sidewalk meets something fixed — a driveway, curb, building foundation or another slab poured at a different time. Expansion joints let each section move independently without cracking against its neighbor.
Bags or ready-mix?
The crossover sits around half a cubic yard, roughly a 30–40 ft run at standard width and thickness. Below that, bags give full control and no delivery minimum. Above it, ready-mix saves substantial mixing labor and gives one continuous pour, which matters for a long, uninterrupted walkway finish.
ADA and slope guidelines
- Running slope5% or less along the direction of travel for a standard accessible path. Steeper runs generally need a ramp with handrails instead.
- Cross slope2% or less side to side, enough for drainage without creating a lean that’s difficult to walk or roll across.
- Minimum widthPublic accessible routes typically require at least 36 inches clear, with wider passing points at intervals.
- SurfaceFirm, stable and slip-resistant — a broom finish is standard for exactly this reason.
Requirements vary by jurisdiction and whether the sidewalk is public or private. Check local code before finalizing a public-facing walkway.
Common mistakes
- Forgetting to add up multiple sectionsA walkway that bends is still one continuous pour of concrete — add every straight run’s length together first.
- Score joints spaced too far apartLong, rectangular panels crack more unpredictably than near-square ones. Keep spacing close to the width.
- Skipping the sub-baseEven a light pedestrian sidewalk needs a compacted base; ground movement cracks concrete regardless of foot traffic.
- Ignoring cross slopeA dead-flat or backward-sloped sidewalk holds puddles and ices over in cold climates.
- Treating a driveway crossing like the rest of the sidewalkAny section vehicles cross needs driveway-grade thickness, typically 6 inches, not standard sidewalk thickness.
- Ordering the exact calculated amountSub-base is never perfectly even. Add waste and round up rather than ordering the bare minimum.
What this calculator assumes
Adjust your result if your project differs from these.
- Each section is a straight, uniform-width rectangle
- Concrete density of 150 lb/ft³ for weight
- Bag yield of 0.60 cu ft for an 80 lb bag
- Score joint spacing set equal to the sidewalk’s width
- Wire mesh, if selected, sized to the full sidewalk area with no deduction for overlap
- Fiber mesh treated as a mix additive with no separate material quantity
- Prices are whatever you enter; they are not live market rates
Common questions
How thick should a concrete sidewalk be?
4 inches is standard for residential sidewalks and most municipal codes. Sections crossed by vehicles, such as a driveway apron, should be poured at 6 inches to match driveway strength.
How wide should a sidewalk be?
3 feet is the minimum for a single-file residential path. 4 feet is the common standard for two people to pass comfortably, and 5 feet or more is typical for accessible or public sidewalks.
How many bags of concrete for a sidewalk?
A 4 ft wide, 50 ft long sidewalk at 4 inches thick needs about 0.62 cubic yards, or roughly 28 bags of 80 lb concrete mix, though ready-mix is usually more practical above about half a yard.
How far apart should score joints be?
Roughly equal to the sidewalk’s width, keeping each panel close to square. A 4 ft wide sidewalk typically gets score joints every 4 to 5 feet.
What is the difference between a score joint and an expansion joint?
A score joint is a shallow groove that controls where the slab cracks within a continuous pour. An expansion joint is a full-depth gap, often filled with flexible material, placed where the sidewalk meets a driveway, curb, building or another fixed structure.
Does a sidewalk need rebar or mesh?
Most residential sidewalks use fiber-reinforced concrete mix rather than a separate mesh or rebar layer. Wire mesh is sometimes used on wider commercial walkways or sections crossed by vehicles.
What is the required slope for an accessible sidewalk?
A running slope of 5% or less along the direction of travel, and a cross slope of 2% or less side to side, are the general ADA guidelines. Steeper runs typically require a ramp with handrails instead.
Can I pour a sidewalk in sections?
Yes, and it’s common for longer walkways. Each pour needs its own forms and should tie into the previous section with a properly placed joint rather than a random cold joint.
How long before I can walk on a new sidewalk?
Light foot traffic is usually fine after 24 to 48 hours. Full design strength is reached at about 28 days.
Do I need a permit for a sidewalk?
Often yes, especially for public-facing sidewalks along a street, since municipalities frequently set specific width, thickness and slope requirements. Check local code before pouring.
Should I use bags or ready-mix for a sidewalk?
Bags are practical up to about half a cubic yard, roughly a short walkway. Longer or wider sidewalks add up quickly and are usually cheaper and easier to finish as a single ready-mix pour.
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Project
| Total length | — |
| Width | — |
| Area | — |
| Thickness | — |
| Reinforcement | — |
| Waste allowance | — |
Volume
| Cubic yards (incl. waste) | — |
| Cubic feet | — |
| Weight | — |
Score joints
| Recommended spacing | — |
| Number of joints | — |
Order
| 80 lb bags | — |
| Ready-mix | — |
| Estimated cost | — |
Notes
Estimate generated by materialcalculate.com. Figures assume rectangular sections of uniform thickness and a concrete density of 150 lb/ft³. Confirm quantities with your supplier before ordering.