Paver Calculator

A paver patio is a stack of layers: pavers on a 1 in bed of sand, over a compacted gravel base, locked in by edge restraints, with sand swept into the joints. Each layer is bought in a different unit (pieces, tons, bags and linear feet), which is why a materials list is easy to get wrong. This paver calculator sizes all of them from one set of measurements and adds a cost line for each.

For an odd-shaped yard, break the area into rectangles with the Square Footage Calculator first. If you would rather pour than lay, the Concrete Calculator sizes a slab of the same footprint.

How many pavers: the formula

Every paver claims its own face plus its share of the joints around it. Paver sizes are usually quoted as nominal sizes: a "4 × 8" concrete paver measures about 3.94 × 7.87 in (100 × 200 mm), and the spacer bars on its sides fill out the rest of the 4 × 8 module. For nominal sizes the count is:

If you know the true face size instead, add the joint to each side: pavers per sq ft = 144 ÷ ((L + J) × (W + J)). ICPI's construction guide calls for joints between 1/16 and 3/16 in. A spec sheet settles the question, because it lists the pieces per square foot for that exact product; tumbled pavers with smaller faces, for example, can run above the count the nominal size suggests.

Worked example: a 12 × 16 ft patio against the house

A patio runs 16 ft along the back wall of the house and 12 ft out into the yard, paved with 2-3/8 in thick 4 × 8 pavers in a 90° herringbone, on a 4 in base:

• Area: 12 × 16 = 192 sq ft; perimeter 56 ft, of which 16 ft is the house wall
• Pavers: 192 × 4.5 = 864, plus 10% for herringbone cuts = 951 pavers (211.3 sq ft, or 2.11 pallets at 100 sq ft each)
• Edge restraint: 56 − 16 = 40 ft; the house wall does that job on the fourth side
• Base area: 192 + 40 × 0.5 ft extension = 212 sq ft
• Base: 212 × 4 ÷ 12 = 70.67 cu ft = 2.62 cu yd × 2.0 = 5.23 tons
• Bedding sand: 192 × 1 ÷ 12 = 16 cu ft = 0.59 cu yd, plus 10% = 0.65 cu yd, or 0.88 tons
• Polymeric sand: 167.0 lb of joint, plus 10% = 183.7 lb, so 4 bags of 50 lb
• Dig depth: 4 in of base + 2-3/8 in paver + 1 in sand − 3/8 in settlement = 7 in below the finished surface

With the example prices in the calculator ($3.50 per sq ft of pavers, $45 per ton of base, $50 per ton of sand, $30 per bag of polymeric sand and $2.50 per ft of edging), the materials come to $739.67 + $235.56 + $44.00 + $120.00 + $100.00 = $1,239.22, about $6.45 per square foot. The 2.11 pallets mean two full pallets plus a partial one, which many yards sell by the piece.

Worked example: an L-shaped driveway

A driveway runs 40 ft from the street, widening to 20 ft at a parking pad, so it measures 40 × 20 ft overall with a 20 × 10 ft corner left as lawn. It meets the garage slab and the street apron along 30 ft of concrete, uses 6 × 9 pavers in a 45° herringbone, and sits on an 8 in base because the soil is clay and the winters are cold:

• Area: 40 × 20 − 20 × 10 = 600 sq ft; perimeter 2 × (40 + 20) = 120 ft
• Pavers: 144 ÷ 54 = 2.667 per sq ft, so 1,600 pavers, plus 15% = 1,840 pavers (690 sq ft, 6.9 pallets)
• Edge restraint: 120 − 30 = 90 ft
• Base area: an 8 in base extends 8 in past the edging, so 600 + 90 × 0.667 = 660 sq ft
• Base: 660 × 8 ÷ 12 = 440 cu ft = 16.30 cu yd, or 32.59 tons, placed and compacted in two 4 in lifts
• Bedding sand: 2.04 cu yd with the allowance, 2.75 tons; polymeric sand 426.1 lb, 9 bags
• Dig depth: 8 + 3 = 11 in

At the same example prices the materials total $4,514.17, of which the base alone is $1,466.67. That is typical for driveways: the stone under the pavers is a bigger share of the job than on a patio, and at 32.6 tons it arrives as truckloads, not bags.

Pavers per 100 sq ft by size

The table applies the formula to the six most common US sizes. The first columns treat the size as nominal; the last column shows the count if the same numbers were the actual face size with a 1/8 in joint added. Cut allowances are rounded up to whole pavers.

Reading the nominal size as actual costs 1 to 5% in the count, most for small pavers: 450 against 429.7 per 100 sq ft for 4 × 8. The cut allowance covers that gap on most jobs, but on a large patio the spec sheet's pieces per square foot is the number to trust.

Paver base calculator: depth and tons

The base carries the load, so it gets the most attention in ICPI's Tech Spec 2, now published by the Concrete Masonry & Hardscapes Association as Tech Note PAV-TEC-002. Patios, sidewalks and other pedestrian areas need at least 4 in of compacted base over well-drained soil, residential driveways at least 6 in, and parking lots and residential streets at least 8 in. Colder climates and continually wet or weak soils require a thicker base, and very weak or saturated soils may call for a base stabilized with cement or asphalt; local standards or an engineer set the exact depth there. The base should be dense-graded aggregate (crusher run or road base), spread and compacted in lifts of 4 to 6 in to at least 98% of standard Proctor density.

Because the depth you design is the compacted depth, the calculator weighs the base at 2.0 tons per compacted cubic yard, the 4,000 lb per cubic yard conversion factor Ohio DOT applies to crushed stone aggregate base compacted in place. Loose in the pile, stone weighs less per yard: the U.S. Army's earthmoving manual (FM 5-434) lists dry gravel at 2,700 to 3,000 lb per loose cubic yard, or 1.35 to 1.5 tons. If your yard sells by the loose cubic yard you therefore need a third to a half more yards than the compacted volume; the loose column below uses 1.5 tons, so treat it as the minimum. The table gives the base for every 100 sq ft of base area:

The extension column is ICPI's rule for how far the base runs past the edge restraint: 6 in for bases up to 6 in deep, a distance equal to the depth from 6 to 10 in, and 10 in beyond that. It keeps the edging spikes in solid stone instead of soil, which matters most where the ground heaves in winter. The bag column shows why bags only suit small jobs: even a 4 in base needs about one 50 lb bag per square foot.

Bedding sand and polymeric joint sand

The bedding layer is concrete sand meeting ASTM C33, screeded to an uncompacted 1 in. ICPI is specific about what not to use: masonry sand, limestone screenings and stone dust. Screenings and stone dust often do not compact uniformly and can keep water from draining sideways through the bedding layer. Never use extra sand to fill low spots in the base, because the dip reappears in the pavers. Every 100 sq ft takes 0.31 cubic yards, or 0.34 cubic yards and 0.46 tons with the 10% allowance the calculator adds for screeding losses. The tons use 2,700 lb per cubic yard, inside the 2,600 to 2,900 lb the Army's FM 5-434 lists for loose dry sand.

The joints get a finer sand meeting ASTM C144, or a polymeric sand whose binder hardens after it is wetted. The calculator figures polymeric sand from the joint volume, filled to 1/8 in below the paver surface at 100 lb per cubic foot, the same dry-sand weight as above. For 2-3/8 in thick pavers, the net weight per 100 sq ft is:

In bags, that puts one 50 lb bag at about 57 sq ft of 4 × 8 pavers with 1/8 in joints, 129 sq ft of 12 × 12 units and 257 sq ft of 24 × 24 slabs. Bag labels give coverage ranges by joint width and paver size, and they are worth comparing with these figures before you buy. Thicker 3-1/8 in pavers have deeper joints: 116.0 lb per 100 sq ft for 4 × 8 at 1/8 in.

Patterns and cut waste

The pattern decides how many pavers end up as offcuts. Running bond and stack bond meet a straight edge square, so cuts are few; the calculator's default for them is 5%. A 90° herringbone meets the edge with a zigzag that needs a cut every other paver, so its default is 10%. A 45° herringbone runs diagonally to every edge and wastes the most, so the default is 15%. These are planning allowances, not a standard, so raise them for a layout with many cuts. ICPI recommends herringbone for all vehicular areas because the interlock resists tires starting, braking and turning. Gaps wider than 3/8 in along the edge should be filled with cut pieces, and on driveways no cut piece should be smaller than a third of a paver. Circles and curved borders add cutting to any pattern, so add about 5% for them.

Edge restraints and dig depth

Edge restraints keep the pavers from spreading apart, and ICPI's Tech Spec 3 treats them as essential. Aluminum, steel, plastic made for pavers, and concrete all work, as do the walls of a building and an existing slab, which is why the calculator subtracts those edges. Soil backfill and garden-bed edging are not acceptable restraints, and the restraint must touch at least 1 in of the paver's side. The calculator's edging figure is the perimeter minus the rigid edges you enter.

The dig depth follows from the layers. ICPI sets the top of the base 3 in below the finished surface for 2-3/8 in pavers on 1 in of sand, which leaves 1/4 in for compaction settling and 1/8 in for minor settling over time. Add the base depth and you have the excavation: 7 in for a 4 in patio base, 11 in for an 8 in driveway base, and 3/4 in more with 3-1/8 in pavers. Slope the dig and the base at least 1.5 to 2% (about 1/4 in per foot) away from the house.

How to use this calculator, and who it is for

1. Choose the shape and enter its dimensions in feet. For an L, measure the full rectangle and then the unpaved corner.
2. Enter rigid edges, the feet of patio that meet a wall, a garage slab or a curb.
3. Pick the paver size and say whether it is nominal or the actual face size, then set the joint.
4. Pick the pattern, which fills in a cut allowance you can overwrite.
5. Set the thickness, base depth and pallet coverage, and leave the ICPI base extension on unless the base is already in place.
6. Enter your prices and read the results: pavers and pallets in the headline, then base, sand, edging, dig depth and a cost table.

Homeowners use it to price a patio before asking for bids and to order the base in one delivery instead of two. Landscapers use the per-100 sq ft tables for quick takeoffs and the cost table to explain a quote line by line. It also helps anyone choosing between paver sizes, since the count, cuts and joint sand change with every option.

Key terms

• Nominal size: the paver's trade size, which includes the joint; the face is slightly smaller.
• Dense-graded base: crushed stone with fines (crusher run, road base) that compacts into a stable layer; graded under ASTM D2940.
• Lift: one layer of base spread and compacted before the next, 4 to 6 in with a plate compactor.
• Bedding sand: the 1 in layer of ASTM C33 concrete sand the pavers are set on.
• Polymeric sand: joint sand with a binder that hardens when wetted, resisting washout and weeds.
• Edge restraint: the border that holds the pavers together, spiked into the base.
• Base extension: the strip of base that runs past the edge restraint to support it.
• ASTM C936: the US paver standard, requiring an average compressive strength of at least 8,000 psi and absorption of no more than 5%.

What changes the result, and tips

• Base depth moves the biggest number: going from 4 to 6 in raises the base by half, and the dig with it.
• Paver size changes the count and the joint sand, not the base. Small pavers mean more pieces and more joint per square foot.
• Pattern adds 5 to 15% to the paver order, more with curves.
• Rigid edges cut both the edging and the base extension, so enter the house wall and any slab you build against.
• Order base and sand for delivery together, and keep them separate on site; base mixed into bedding sand ruins the screed.
• Pull pavers from several bundles at once, as ICPI advises, so slight color differences blend across the patio.

Limitations

The calculator assumes level, firm subgrade and a single base layer of dense-graded aggregate. Poor soils may need geotextile, a sub-base of larger stone or a stabilized base, and permeable pavers use open-graded stone and no sand at all. The densities are typical values: real base weighs more when wet and less when it holds little fines, so ask the quarry for its figure. Piece counts follow the size you enter, while a brand's spec sheet lists the exact pieces per square foot and per pallet. Steps, seat walls, borders of a different paver and the corners of the base extension (about 1 sq ft each) are not counted.

Related calculators

For a gravel path or the stone around the patio, the Gravel Calculator and the Stone Calculator size loose aggregate by depth. The Sand Calculator handles bulk sand for other jobs, and the Concrete Calculator covers a poured footing, curb or slab. Use the Square Footage Calculator for areas made of several rectangles, and if the project moves indoors, the Grout Calculator sizes grout and thinset for tile.

Sources

• Concrete Masonry & Hardscapes Association (CMHA, which absorbed ICPI), Tech Note PAV-TEC-002-22, Construction of Interlocking Concrete Pavements (formerly ICPI Tech Spec 2, revised 2022): paver thickness, base depths, lifts and compaction, bedding sand, joint widths, patterns, cuts, saw dust and utility marking.
• CMHA, Tech Note PAV-TEC-003-22, Edge Restraints for Interlocking Concrete Pavements (formerly ICPI Tech Spec 3, revised 2022): restraint types, base extension and base elevation below the finished surface.
• CMHA, PAV-MAN-006-20, Construction Tolerances for ICP (ICPI guide revised February 2020): base extension table, minimum base thickness, aspect ratio, slope, herringbone for vehicular areas and cut pavers.
• Ohio Department of Transportation, Construction and Material Specifications, Item 304 Aggregate Base, Table 304.07-1: 4,000 lb per cubic yard for crushed stone and crushed gravel base, measured compacted in place.
• U.S. Department of the Army, FM 5-434, Earthmoving Operations (June 2000, PDF copy), Table 1-2: loose weights of dry sand (2,600 to 2,900 lb per cubic yard) and dry gravel (2,700 to 3,000 lb).
• U.S. Occupational Safety and Health Administration, 29 CFR 1926.1153, Respirable crystalline silica: Table 1 controls for handheld power saws.
• National Institute of Standards and Technology (NIST), unit conversion: cubic feet, cubic yards and tons.
• ASTM International: C936 (solid interlocking concrete paving units), C33 (concrete aggregates, bedding sand), C144 (masonry sand, joint sand) and D2940 (graded aggregate for bases).