Formula
The paver module is the paver plus the joint, on both sides, in square feet. The count is the patio area divided by that module, times the waste, rounded up. Running bond and stack bond start at 5% waste. Basketweave is 7%. A 45° herringbone or a diagonal is 10%. Curves and a fan are 15%.
module = (length + joint) × (width + joint) ÷ 144
pavers = ceil(area ÷ module × (1 + waste ÷ 100))
base yards = base area × depth × (1 + compaction) ÷ 27
sand = patio area × bedding depth × (1 + waste)
A rectangle’s base is the patio plus the extension on every side. A circle grows by the same extension on the diameter. A triangle or a square footage you type uses area plus perimeter times the extension, which misses the outside corners and is labeled approximate. Bedding sand covers the paver area only, usually 1 inch, screeded over the compacted base. It is concrete sand, the ASTM C33 gradation, not the joint sand.
The build-up is a compacted subgrade, a geotextile on a soft soil, crushed-stone base compacted in lifts of about 2 to 4 inches, the bedding sand, the pavers, and then the joint sand. Edge restraint runs the perimeter that is not against a house or a slab. Spikes follow the spacing. None of this is a structural load rating.
Worked examples
12 × 16 ft, 4 × 8 in, ⅛ in joints, 5% waste. 867 pavers. At 10% herringbone waste the same patio is 908.
Base, 6 in, 6 in extension, 20% compaction, 1.4 ton/yd³. 221 ft², 4.91 yd³, 6.88 tons.
Bedding sand, 1 in, 10% waste. 0.65 yd³, 0.88 tons, 36 bags of 0.5 ft³.
One 16 ft side against the house. 40 ft of edging, 5 pieces of 8 ft, 40 spikes at 12 in.
100 sq ft of 6 × 9 in pavers, no joint, no waste. 267 pavers.
Reference
Pedestrian base on this page starts at 6 inches, inside a 4–6 inch guideline. A driveway starts at 8 inches, inside an 8–12 inch guideline. Crushed stone is 2,800 lb/yd³. Bedding sand is 2,700 lb/yd³.
Questions
How many pavers are in a square foot?
A 4 × 8 in paver with no joint is 4.5 per square foot. With a ⅛ inch joint the module is a little larger, about 4.3 per square foot. The joint and the waste still have to be added.
How much paver base do I need for a 12 × 12 patio?
At 6 inches of compacted base and a 6 inch extension, the base is 13 × 13 ft, 0.5 ft deep. Before compaction that is 84.5 cubic feet. At 20% more for compaction it is about 3.76 cubic yards, about 5.26 tons at 1.4 ton per yard. Change the size for your patio.
How deep should a paver base be?
A typical pedestrian patio or walk is about 4 to 6 inches of compacted crushed stone. A driveway is often 8 to 12 inches, and deeper on clay or a soil that drains poorly. Those are guidelines. A driveway, a poor soil, or a permeable paver follows the manufacturer or a designer.
How much sand goes under pavers?
The screeded bedding layer is usually 1 inch of concrete sand, and this page allows ¾ to 1½ inches. It is not the base. Polymeric joint sand, after the pavers are in, is the sand calculator.
How many extra pavers does herringbone need?
This page uses 10% waste for a 45° herringbone or a diagonal, against 5% for a running bond. On the 12 × 16 ft example that is 908 pavers instead of 867. Curves and a fan are set at 15%.
Do I need edging?
The edge restraint keeps the field from spreading. A side against a house or a slab does not need a piece of edging. The rest of the perimeter is divided by the piece length, and spikes follow the spacing you set.
How many tons of gravel are in a paver patio?
The 12 × 16 ft example, 6 inches deep with a 6 inch extension and 20% compaction, is about 4.91 cubic yards and 6.88 tons at 1.4 ton per yard. The gravel calculator is the same stone used for other jobs.
Sources
- Concrete Masonry & Hardscapes Association, formerly the Interlocking Concrete Pavement Institute. Installation guidance for interlocking concrete pavement is the source of the 1 inch bedding layer, the base that extends past the edge, and the edge restraint. The depths here are typical guidelines, not a site design.
- ASTM C33, concrete sand, for the bedding layer. ASTM D2940 is the dense-graded aggregate specification many road bases follow. This page uses 2,800 lb/yd³ as a planning weight for that crushed stone. The delivery ticket wins.
- Polymeric joint sand is the sand calculator. Other stone orders are the gravel calculator.