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Concrete Sidewalk Calculator

Estimate a concrete sidewalk or walkway. Enter the length, width and thickness for the cubic yards and bag count — and because a long thin slab lives or dies on its joints, the calculator also works out how many control joints you need and how far apart they go.

Concrete for the sidewalk
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    How it works

    Volume (cu ft) = length × width × (thickness ÷ 12); cubic yards = cu ft ÷ 27. Control joints follow the standard rule that maximum spacing in feet is about 2.5 × the slab thickness in inches, so a 4 in walk allows joints up to 10 ft apart. Most sidewalks are jointed at the walk width instead, giving square panels, so the calculator uses whichever spacing is smaller.

    Frequently asked questions

    How much concrete for a sidewalk?

    A 40 ft long, 4 ft wide walk at 4 inches is 53.3 cubic feet, or about 1.98 cubic yards before waste. Order to the next quarter yard and keep a 10% cushion.

    How thick should a sidewalk be?

    Four inches is standard for a residential walkway. Go to 5–6 inches where a vehicle may cross it, such as at a driveway apron, and keep the compacted base uniform underneath.

    How far apart should sidewalk control joints be?

    Maximum spacing in feet is roughly 2.5 times the thickness in inches — 10 ft for a 4 in slab. In practice sidewalks are jointed at the walk width so the panels stay square, which for a 4 ft walk means a joint every 4 ft. Square panels crack far less than long ones.

    Why does concrete crack without joints?

    Concrete shrinks as it cures and will crack somewhere to relieve that stress. Control joints simply decide where: they create a weakened plane so the crack forms straight and out of sight, rather than wandering across the surface.

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    Estimates are for planning only. Material yields, densities and code requirements vary — confirm quantities with your supplier and local building code before ordering.