How Much Concrete for a Sidewalk? Yards per Foot

How much concrete for a sidewalk is easiest to figure per running foot. A walk 4 feet wide and 4 inches thick uses 1.33 cubic feet of concrete for every foot of length, so one cubic yard covers about 20 feet. A 3-foot walk stretches a yard to about 27 feet, and a 5-foot walk shrinks it to about 16 feet. Once you know the length, the rest is simple multiplication.

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Concrete per foot of sidewalk

Width	Thickness	Cubic feet per foot	Feet per cubic yard
3 feet	4 inches	1.00	27
4 feet	4 inches	1.33	20.3
5 feet	4 inches	1.67	16.2
4 feet	5 inches	1.67	16.2
5 feet	6 inches	2.50	10.8

To find cubic yards for your walk, divide its length by the feet-per-yard figure. A 4-foot walk that runs 50 feet takes 50 ÷ 20.3 = 2.46 cubic yards, or about 2.65 with 8 percent extra.

How wide and how thick

Residential walk to the door: 3 to 4 feet wide is common. Four feet lets two people walk side by side.
Public sidewalk: many towns set a minimum of 4 or 5 feet, and accessibility guidelines call for enough width for a wheelchair to pass. If you are replacing a sidewalk along the street, the town usually sets width, thickness, and slope.
Thickness: 4 inches is typical for foot traffic. Where a driveway crosses the walk, the crossing section is usually thickened to 6 inches because it carries car tires.

Bags or ready-mix

At about 0.6 cubic feet per 80-pound bag, a 4-foot walk 4 inches thick uses about 2.2 bags per foot. A 20-foot walk is about 45 bags, which is manageable over a day if you pour it in sections between form boards. Past roughly 30 feet, a ready-mix truck usually saves time and gives a more even finish, especially if the truck can back up alongside the forms.

Other parts of a sidewalk job

Base: 4 inches of compacted crushed stone is common. For a 4-foot walk, that is about 1.33 cubic feet per foot, or roughly 0.07 tons per foot. A 50-foot walk takes about 3.5 tons.
Cross slope: a slight tilt, often around 1/4 inch per foot, lets water run off to one side instead of pooling.
Joints: control joints are commonly spaced about as far apart as the walk is wide, so a 4-foot walk gets a joint every 4 to 5 feet. Expansion joints go where the walk meets the house, steps, or driveway.
Steps: if the walk climbs to a porch, figure the steps separately; see how much concrete for steps.

Curves and odd shapes

For a curved path, measure along the centerline of the walk to get its length, then use the per-foot figures. For a walk that widens at a landing, figure the landing as a separate rectangle and add it. When in doubt, the concrete calculator takes each section’s length, width, and depth.

Concrete or asphalt?

Concrete is the usual choice for walks because it holds a crisp edge and a broom finish gives good grip. Some homeowners match the walk to an asphalt driveway; our guide to an asphalt walkway from the drive to the door compares the two.

Questions people ask

How much concrete do I need for a 4 foot wide sidewalk?

At 4 inches thick, about 1.33 cubic feet per foot of length, so one cubic yard covers roughly 20 feet.

How thick should a sidewalk be?

Four inches is typical for foot traffic. Sections where cars cross, such as at a driveway, are usually 6 inches thick.

How many bags of concrete for a sidewalk?

About 2.2 bags of 80-pound mix per foot for a 4-foot walk 4 inches thick. A 20-foot walk needs about 45 bags.

How far apart should sidewalk joints be?

Commonly about as far apart as the walk is wide, so every 4 to 5 feet on a 4-foot walk.

Do I need gravel under a sidewalk?

A compacted crushed stone base of about 4 inches is common, especially on clay or poorly drained soil.

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