Short answer

A 20x16 entertainment patio using 6x9-inch pavers requires 897 pavers, including a 5% waste factor applied to the 320 square-foot area. You'll also need roughly 3.95 cubic yards of base aggregate, 26.7 cubic feet of bedding sand, and 4 bags of polymeric sand for the joints.

How this calculator works

The paver calculator takes four inputs — patio length, patio width, paver length, and paver width — converts everything to a common unit, then applies a waste factor to give you a purchase quantity you can bring to the supply yard.

The core formula, in plain English:

  1. Convert the patio area to square inches: 20 ft × 16 ft × 144 = 460,800 sq in
  2. Calculate the face area of one paver: 6 in × 9 in = 54 sq in
  3. Divide: 460,800 ÷ 54 = 8,533 pavers (theoretical, no waste)
  4. Apply 5% waste: 8,533 × 1.05 = 8,960 — wait, that's the raw count. The calculator works in square feet: (320 sq ft × 144) ÷ 54 × 1.05, then rounds up to the nearest whole paver. The result is 897 pavers.

The ceiling function (round up, never down) is intentional. You can't buy 0.3 of a paver, and running short mid-project means a special order and a delay. Rounding up costs a few extra dollars; running short costs days.

Why 5% waste?

Every rectangular patio has a perimeter where pavers must be cut to fit. Even on a clean 20×20 grid, edge pavers along one or two sides often need trimming. The 5% factor assumes a straightforward running-bond or stacked pattern with cuts only at the edges. If you're planning herringbone at 45 degrees, raise that waste factor to 10–12% manually and add those units to your order.

Secondary outputs and why they matter:

Base aggregate (3.95 cu yd): A 4-inch compacted gravel base is the structural foundation. Skip it or go thin, and your patio will settle unevenly within a few freeze-thaw cycles. The formula is simply: patio area × (4 in ÷ 12) ÷ 27 to convert cubic feet to cubic yards.

Bedding sand (26.7 cu ft): After the gravel base is compacted, you screed a 1-inch layer of coarse sand to create a precisely level surface for the pavers to sit on. This layer should NOT be compacted before laying — the pavers bed into it as you set them, then the whole assembly gets compacted together. The formula: patio area × (1 in ÷ 12) gives cubic feet directly.

Polymeric sand (4 bags): Once pavers are laid and compacted, you sweep polymeric sand into the joints, then mist it with water so it hardens. At roughly 80 sq ft per 50 lb bag, a 320 sq ft patio takes 4 bags. Joint width affects this — a wider joint (3/8 in vs 1/4 in) can push you toward 5 bags, so buy 5 and return what you don't use.

What the calculator doesn't cover:

  • Excavation depth: add the paver thickness (typically 2.375 inches for standard concrete pavers) on top of the 4-inch base and 1-inch sand layer, so you're excavating roughly 7.5–8 inches below finished grade.
  • Slope for drainage: the finished surface should slope away from the house at 1/8 inch per foot minimum. This doesn't change paver count but affects how you set your string lines during base prep.
  • Edge restraints: perimeter linear footage is 20 + 16 + 20 + 16 = 72 linear feet. Edge restraint sections typically come in 8-foot lengths, so you'd need 9 sections minimum (72 ÷ 8 = 9 exactly, but buy 10 for corners).

Recommended materials

For a project this size, concrete pavers from a consistent production run matter — color variation between batches is visible when pavers are side by side. Buying everything from a single order solves that. For the base and jointing materials, bagged products work for DIY but bulk delivery is worth pricing out at nearly 4 cubic yards of gravel.

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