How to calculate a patio
A poured patio uses a 4 inch slab, while a paver patio uses a stone base and a sand layer instead.
- Measure the patio length and width, including steps or a wider apron.
- For concrete, use 4 inches. For pavers, plan 4 inches of compacted stone plus 1 inch of sand.
- Calculate each layer separately.
- Add a small percentage for waste, and round up to a ready mix minimum if needed.
Worked example
For a typical patio with length 12 ft, width 14 ft, depth 4 in, the volume is 56.00 cubic feet. Divide by 27 for 2.07 cubic yards. With a 10 percent allowance, plan for 2.28 cubic yards.
In concrete, 2.07 cubic yards weighs about 4.20 US tons at a planning value of 4,050 pounds per cubic yard.
Patio 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 |
|---|---|---|---|---|
| 10 by 10 ft, 4 in | 33.33 | 1.23 | 1.36 | 2.50 |
| 12 by 14 ft, 4 in | 56.00 | 2.07 | 2.28 | 4.20 |
| 16 by 20 ft, 4 in | 106.67 | 3.95 | 4.35 | 8.00 |
| 20 by 24 ft, 4 in | 160.00 | 5.93 | 6.52 | 12.00 |
Tips
- Slope the patio about a quarter inch per foot away from the house.
- Mark the finished height first, then work down through the layers.
- Use the paver base and sand calculators for a paver patio.
Common mistakes to avoid
- Planning a flat patio that drains toward the house.
- Using only the surface area and forgetting the base layers.
- Rounding down a measurement that is a few inches short.
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 patio?
Multiply the dimensions in feet and divide by 27. The example above, length 12 ft, width 14 ft, depth 4 in, needs 2.07 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 patio material weigh?
2.07 cubic yards of concrete weighs about 4.20 US tons as a planning value.