How Much Concrete for a Sidewalk?
Quick answer: a 10-foot walk, 3.5 feet wide, 4 inches thick ≈ 0.43 cubic yards. Length × width × thickness ÷ 27, then add 10% for a smooth pour.
- The volume formula
- Thickness rules
- Yards by walk size
- Bags vs ready-mix
- Worked example: 10×3.5 walk
- FAQ
The volume formula
Volume = length × width × thickness, all in feet, then divide by 27 for cubic yards. A 10×3.5 walk at 4 inches: 10 × 3.5 × 0.333 = 11.67 cu ft ÷ 27 ≈ 0.43 cubic yards.
Thickness rules
4 inches for a residential walkway carrying foot traffic; 5 inches where wheelbarrows or bikes roll often; 6 inches where a vehicle crosses. These are the minimums — most pros pour 4 inches for a standard walk.
| Walk size (3.5 ft wide) | 4-in thick | 6-in thick |
|---|---|---|
| 10 ft | 0.43 yd | 0.65 yd |
| 20 ft | 0.86 yd | 1.30 yd |
| 40 ft | 1.73 yd | 2.59 yd |
| 60 ft | 2.59 yd | 3.89 yd |
Bags vs ready-mix
Bagged concrete works for walks up to about 20–25 feet — it's flexible and avoids a delivery minimum. An 80lb bag yields about 0.6 cu ft; a 60lb bag about 0.45 cu ft. For longer runs, a ready-mix truck is cheaper and more consistent.
Worked example: a 10-foot walk, 4 inches thick
- Area = 10 × 3.5 = 35 sq ft
- Volume = 35 × 0.333 = 11.67 cu ft
- ÷ 27 = 0.43 cubic yards
- 80lb bags: 11.67 ÷ 0.6 = 20 bags (with 10% waste)
FAQ
A 10-foot-long, 3.5-foot-wide walk at 4 inches thick needs about 0.43 cubic yards — length × width × thickness ÷ 27.
4 inches for foot traffic, 5 inches for frequent wheelbarrow traffic, and 6 inches where a vehicle might cross.
About 20 80lb bags (or 26 60lb bags) for a 10×3.5 foot walk at 4 inches thick, including 10% waste. The walk needs 11.67 cu ft ÷ 0.6 = 19.4 bags — round up to 20.
Volume = length × width × thickness, all in feet, divided by 27 for yards. Add 10% for a smooth pour.
Yes for short walks up to about 20–25 feet. For longer runs, a ready-mix truck is cheaper and more consistent.