How to calculate a sidewalk
Walks are long and narrow, so a small change in width makes a big change in volume.
- Measure the total walk length, following any turns.
- Measure the width, which is commonly 3 to 5 feet.
- Use a 4 inch thickness for residential walks.
- Add 5 to 10 percent for waste.
Worked example
For a typical sidewalk with length 30 ft, width 4 ft, depth 4 in, the volume is 40.00 cubic feet. Divide by 27 for 1.48 cubic yards. With a 10 percent allowance, plan for 1.63 cubic yards.
In concrete, 1.48 cubic yards weighs about 3.00 US tons at a planning value of 4,050 pounds per cubic yard.
Sidewalk sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra | US tons |
|---|---|---|---|---|
| 20 by 3 ft, 4 in | 20.00 | 0.74 | 0.81 | 1.50 |
| 30 by 4 ft, 4 in | 40.00 | 1.48 | 1.63 | 3.00 |
| 50 by 4 ft, 4 in | 66.67 | 2.47 | 2.72 | 5.00 |
| 100 by 5 ft, 4 in | 166.67 | 6.17 | 6.79 | 12.50 |
Tips
- Wider walks feel safer and are easier to shovel.
- Use a gravel base 4 inches thick to limit frost damage.
- Check local rules on width and slope.
Common mistakes to avoid
- Forgetting to include the base.
- Measuring only the straight sections.
- Not allowing for steps or ramps.
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How many cubic yards do I need for a sidewalk?
Multiply the dimensions in feet and divide by 27. The example above, length 30 ft, width 4 ft, depth 4 in, needs 1.48 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
How much does sidewalk material weigh?
1.48 cubic yards of concrete weighs about 3.00 US tons as a planning value.