Key takeaways
- Include the joint in the count, as it changes the pavers per square foot.
- ICPI's application guide uses a nominal 1 inch of bedding sand.
- Base depth depends on your soil and use, so it's your entry rather than our figure.
Enter your area, the paver's actual size and your layer depths. The 6-inch base is only an example, so change it to what your paver maker or installer recommends.
How the calculator works
- Pavers per square foot: 144 ÷ ((length + joint) × (width + joint))
- Pavers to buy: area × (1 + waste %) × pavers per square foot, rounded up
- Sand or base: area × depth in inches ÷ 324, in cubic yards
Worked example
A 12 × 10 foot patio with 4 × 8 inch pavers, a 1/8-inch joint and 5% waste:
- 144 ÷ (8.125 × 4.125) = 4.30 per square foot
- 120 × 1.05 × 4.30 = 542 pavers
- 1 inch of sand: 120 × 1 ÷ 324 = 0.37 cubic yards
- 6 inches of base: 120 × 6 ÷ 324 = 2.22 cubic yards
What each layer does
ICPI's application guide describes the system from the bottom up:
- Compacted soil subgrade, with geotextile if the design requires it
- Compacted aggregate or stabilized base, suited to your traffic and environment
- Bedding sand, nominally 1 inch thick. It says to screed to 1 to 1 1/2 inches uncompacted, and not to use sand to fill depressions in the base
- Pavers, compacted, with sand swept into the joints and compacted again
- Edge restraints, which hold the system together. For walks, patios and driveways, it lists options such as steel, aluminum, concrete and plastic edging designed for pavers
How deep should the base be?
We didn't find a single figure to give you. ICPI's guide says the base should suit your traffic and environment, and depth depends on your soil, climate and use. Advice online varies, so ask your paver maker or a certified installer. Here's what different depths mean for this patio:
| Base depth | Cubic yards on 120 sq ft |
|---|---|
| 4 in | 1.48 |
| 6 in | 2.22 |
| 8 in | 2.96 |
| 12 in | 4.44 |
Material also compacts, so the amount delivered needs to be more than the finished volume. Ask your supplier how much to add.
Paver thickness
ICPI's guide recommends 2 3/8-inch thick pavers for pedestrian uses and residential driveways, and says pavements with vehicle traffic typically need 3 1/8 inches. It also has limits on paver shape for vehicle use, so check with the maker.
Before you dig
- Excavate for the pavers, sand and base together.
- Slope the surface so water runs away from your house. See gutter and drainage for the IRC's grading figure.
- Contact 811 a few business days ahead.
For the base, you can also compare with the gravel calculator to estimate weight.
Frequently asked questions
How many pavers do I need for a 10 × 12 patio?
With 4 × 8 inch pavers and a 1/8-inch joint, about 516 before waste, or 542 with 5%.
How much sand do I need under pavers?
For 1 inch across 120 square feet, about 0.37 cubic yards. ICPI's guide uses a nominal 1 inch.
Can I use sand to level a low spot?
ICPI's guide says not to use sand to fill depressions in the base, so fix the base first.
Sources
We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.
- ICPI: Tech Spec 10, Application Guide for Interlocking Concrete Pavements (a copy hosted by a supplier)
- 811: What is 811?