Patio Calculator
Two Very Different Materials, Two Very Different Math Problems
A paver patio and a poured concrete slab are priced and ordered in completely different units — one by the piece, one by the cubic yard — even though they're solving the same problem of covering a rectangular outdoor space. This calculator switches between the two so you're ordering in the unit your supplier actually sells.
The Formula
Pavers: Pavers Needed = Patio Area ÷ Paver Area
Concrete: Volume = Patio Area × (Thickness ÷ 12)
For pavers, the calculator divides the total patio area by the footprint of a single paver (converted from inches to square feet) and adds a 10% allowance for cuts and breakage along edges and around curves. For a concrete slab, it converts the thickness from inches to feet, multiplies by the area to get cubic feet, then divides by 27 to reach cubic yards.
Where This Calculation Matters
- Ordering pavers by the pallet — suppliers sell pavers per unit or per pallet quantity, so an accurate count avoids either a mid-project supply run or a stack of leftover pavers.
- Sand base preparation — a paver patio needs a compacted sand bedding layer beneath it; the calculator estimates this at the standard 1-inch depth.
- Concrete slab patios — poured patios follow the same cubic-yard math as any other slab, with 80 lb bags as an option for smaller pours.
Worked Example: Paver Patio
A 20 ft × 15 ft patio (300 sq ft) laid with 12 in × 6 in pavers:
| Step | Calculation | Result |
|---|---|---|
| Patio area | 20 × 15 | 300 sq ft |
| Paver area | (12⁄12) × (6⁄12) | 0.5 sq ft |
| Pavers needed (raw) | 300 ÷ 0.5 | 600 |
| Pavers with 10% waste | 600 × 1.10 | 660 pavers |
How to Use This Calculator
- Choose the material — Pavers or Concrete Slab.
- Enter the Patio Length and Patio Width in feet.
- For pavers, enter the Paver Length and Paver Width in inches. For a concrete slab, enter the Slab Thickness in inches.
- Select Calculate to see the number of pavers (with waste allowance) or the concrete volume in cubic yards, plus an estimated bag count for smaller concrete pours.
Related Calculations
Pouring the concrete version instead? The Concrete Calculator covers slabs and footings in more detail, and the Gravel Calculator handles the base layer many patios sit on.