How Much Concrete for a 3x40 Sidewalk?
A sidewalk 3 feet wide and 40 feet long is 120 square feet. Poured 4 inches thick, that is 1.48 cubic yards. How much concrete for a 3x40 sidewalk with a 10 percent allowance: about 1.63 yards.
Concrete calculator →Step-by-step
- Area: 3 × 40 = 120 sq ft.
- Volume: 120 × (4 ÷ 12) = 40.0 cu ft.
- Yards: ÷ 27 = 1.48 yd³.
- Bags instead: 67 bags of 80 lb mix (89 of 60 lb).
Related: How Much Gravel for a 3x40 Walkway?
Concrete by thickness
| Thickness | Cubic feet | Cubic yards | Yards +10% | 80 lb bags | 60 lb bags |
|---|---|---|---|---|---|
| 4 in | 40.0 | 1.48 | 1.63 | 67 | 89 |
| 5 in | 50.0 | 1.85 | 2.04 | 84 | 112 |
| 6 in | 60.0 | 2.22 | 2.44 | 100 | 134 |
How thick a sidewalk should be
Most residential sidewalks are 4 inches thick on a compacted gravel base. Thicken any section that a car, mower or delivery cart will roll over, especially where the walk meets the drive.
Related: How Much Pea Gravel for a 3x40 Walkway?
Joints along the walk
Walks are usually jointed every 4 to 6 feet, often at a spacing equal to the walk width, so a 3-foot walk gets a joint about every 3 feet: roughly 12 joints over 40 feet. Square panels crack less than long, thin ones.
How to buy it
At 1.48 yards, a ready-mix truck is usually easier than bags. Long walks are often poured in sections, so ask the plant how long the truck can wait and whether there is a short-load fee.
Slope and finish
Give the walk a slight cross slope, around 1/4 inch per foot, so water sheds to one side. A light broom finish across the walk gives grip when it is wet.
Questions people ask
How many yards of concrete for a 3x40 sidewalk?
About 1.48 cubic yards at 4 inches thick.
How many bags for a 3x40 sidewalk?
About 67 bags of 80 lb concrete at 4 inches.
How thick should a sidewalk be?
Four inches for foot traffic, 6 inches where vehicles cross.
How far apart should sidewalk joints be?
About every 3 feet for a 3-foot-wide walk, keeping panels close to square.
Should I add extra for waste?
Yes. Adding 5 to 10 percent covers uneven base, spillage and form bulges.
Related guides
- Concrete Sidewalk Thickness for Walks and Crossings
- How Much Concrete for a Sidewalk? Yards per Foot
- How Much Area Does a Yard of Concrete Cover?
- How Many Bags of Concrete in a Yard? 40, 60, 80 lb
- Gravel Base Under a Concrete Slab: Depth and Tons
- How Many Yards in a Concrete Truck? Mixer Sizes
- Concrete Short Load Fee: What It Is and How to Cut It
- 60 lb vs 80 lb Concrete Bags: Yield, Count, and Cost
- Rebar vs Wire Mesh in a Slab: Which One to Use
- How Much Concrete for a 3x25 Sidewalk?
- How Much Concrete for a 3x30 Sidewalk?
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