Paver Patio Calculator: Pavers, Base Gravel and Bedding Sand

How the numbers are worked out

Pavers. A square foot is 144 square inches. Divide by the face area of one paver to get pavers per square foot, multiply by the patio area, then add your cutting margin and round up. For a 120 square foot patio in 4 × 8 inch pavers: 144 ÷ 32 = 4.5 per square foot, × 120 = 540 pavers, + 10% = 594.

Base. Area × base depth in inches ÷ 12 = cubic feet; ÷ 27 = cubic yards. For 120 square feet at 4 inches: 40 cubic feet, about 1.48 cubic yards.

Bedding sand. The same formula at the sand depth. At 1 inch, 120 square feet takes 10 cubic feet, about 0.37 cubic yards.

The layers of a paver patio

The concrete paver industry's homeowner guide describes the standard build-up:

1. Compacted subgrade. The native soil, excavated and compacted. On clay or silt soils, and on soils that stay wet much of the year, a geotextile fabric is recommended between the soil and the base.
2. Compacted aggregate base. Crushed stone compacted in layers. For pedestrian areas such as patios and walkways, a minimum 4 inch thickness is recommended.
3. Bedding sand. Screeded to a consistent thickness between 3/4 inch and 1-1/2 inches; detail drawings show 1 inch.
4. Pavers, compacted into the sand, then joint sand swept in and compacted again.

The guide also says the patio should slope away from the house at a minimum of 2% for drainage. That is about 1/4 inch per foot.

Compacted vs loose base

The base depth in the guides is the finished, compacted thickness. Crushed stone delivered loose takes up more room than it will after compaction, so a truck load of exactly the compacted volume will come up short. Suppliers know how their material compacts and can tell you how much to order. This is one reason the calculator labels the base figure as compacted.

Excavation depth

Add the layers together to see how deep to dig: base + sand + paver thickness, minus any height you want the patio to sit above the surrounding ground. For a 4 inch base, 1 inch of sand and 2-3/8 inch pavers (a common thickness the guide mentions for patios and residential driveways), that is about 7-3/8 inches below the finished patio surface. Call 811 before digging.

Cutting margin

Straight-edged patios laid in a simple pattern have the fewest cuts. Curved edges, circles, herringbone and diagonal layouts create more cut pieces and more waste. Many installers order 5–10% extra for simple layouts and more for complex ones. Leftover pavers are worth keeping for future repairs, since colours vary between production runs.

Measuring

Measure the finished patio outline, not the excavation. For curved or irregular shapes, our measuring guide shows how to split the area into simple shapes.

Common questions

How many 4 by 8 pavers per square foot?

4.5. A 4 × 8 inch paver covers 32 square inches, and a square foot is 144 square inches, so 144 ÷ 32 = 4.5. Real pavers are often slightly smaller than their name, so check the product sheet.

How much base gravel for a 10 by 12 patio?

At a 4 inch compacted depth, 120 square feet needs 40 cubic feet, or about 1.5 cubic yards measured compacted. Order more loose material than that because it compacts; ask your supplier how much extra for their stone.

Can I use more base than 4 inches?

Yes. Four inches is the minimum for pedestrian areas in the industry guide. Contractors may use more on clay, wet or disturbed soils, and driveways need more. Enter the depth you plan to use.

Do I need joint sand too?

Yes, after the pavers are laid and compacted, dry joint sand is swept into the joints. It is a small quantity; the bag will list approximate coverage.