Paver Calculator
With area length 20 ft, area width 12 ft, paver length 8 inch, paver width 4 inch and 3 more fields, paver comes to 1,135 pavers — pavers to buy. It is reached in 7 steps, the last of which is ceil(1031.1608 * (1 + 10 / 100)), and each one is printed on the page with its numbers filled in. The formula is the one published by Interlocking Concrete Pavement Institute, not an approximation fitted to it.
How many pavers a patio or walkway needs at a given paver size and joint width, plus the sand and gravel underneath.
Formula and sources checked · How we check
Area length 20 ft, Area width 12 ft, Paver length 8 inch, Paver width 4 inch
1,135 pavers
Pavers to buy for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Area to cover
20 * 12240 sq ft- Each paver with its joint
((8 + 0.125) * (4 + 0.125)) / 1440.233 sq ft- Pavers before cuts
240 / 0.23274741,031.161 pavers- Pavers to buy
ceil(1031.1608 * (1 + 10 / 100))1,135 pavers- Gravel base
(240 * (4 / 12)) / 272.963 cu yd- Bedding sand at 1 in
(240 * (1 / 12)) / 270.741 cu yd- Edge restraint
2 * (20 + 12)64 ft
Several at once
A job is rarely one of anything. Work out the first, add it, change the figures and add the next — the list keeps what each line was, and totals them.
Worked example
A 20 × 12 ft patio in 8 × 4 in pavers is 240 sq ft. Each paver with its joint covers 0.2327 sq ft, so 1,031 fit and 1,135 gets bought once 10% is added for cuts. Underneath it: 2.96 cubic yards of base and 0.74 of bedding sand.
How to work it out yourself
- 1.Multiply the area length by its width for square feet.
- 2.Add the joint width to each paver dimension, multiply the two and divide by 144 — that is what one paver actually occupies.
- 3.Divide the area by that figure, then add for cuts: 5% on a rectangle, 15% on a herringbone.
- 4.Base and bedding are volumes: area times depth in feet, divided by 27 for cubic yards.
How far one cubic yard goes
A cubic yard is 27 cubic feet. Spread one inch deep it covers 324 square feet, and every other depth is that figure divided by the depth in inches — which is the whole table in one sentence.
| Depth | Square feet | Square yards |
|---|---|---|
| 1 in | 324 | 36.0 |
| 2 in | 162 | 18.0 |
| 3 in | 108 | 12.0 |
| 4 in | 81 | 9.0 |
| 6 in | 54 | 6.0 |
| 8 in | 41 | 4.5 |
| 10 in | 32 | 3.6 |
| 12 in | 27 | 3.0 |
Cubic yards for a given area
| Area | 1 in | 2 in | 3 in | 4 in | 6 in | 8 in | 10 in | 12 in |
|---|---|---|---|---|---|---|---|---|
| 100 sq ft | 0.31 | 0.62 | 0.93 | 1.23 | 1.85 | 2.47 | 3.09 | 3.70 |
| 200 sq ft | 0.62 | 1.23 | 1.85 | 2.47 | 3.70 | 4.94 | 6.17 | 7.41 |
| 500 sq ft | 1.54 | 3.09 | 4.63 | 6.17 | 9.26 | 12.35 | 15.43 | 18.52 |
| 1,000 sq ft | 3.09 | 6.17 | 9.26 | 12.35 | 18.52 | 24.69 | 30.86 | 37.04 |
Suppliers deliver in whole or half yards, so round up — a truck will not bring 2.37.
Bags to the cubic yard
| Bag | Holds | Bags per yard |
|---|---|---|
| Mulch, 2 cu ft bag | 2 cu ft | 14 |
| Mulch, 3 cu ft bag | 3 cu ft | 9 |
| Topsoil or compost, 1 cu ft bag | 1 cu ft | 27 |
| Concrete mix, 80 lb bag | 0.6 cu ft | 45 |
| Concrete mix, 60 lb bag | 0.45 cu ft | 60 |
| Concrete mix, 40 lb bag | 0.3 cu ft | 90 |
Concrete is sold by weight and the yield is printed on the bag, which is why it takes 45 of the 80 lb bags to make a yard rather than the dozen people expect. Past about ten bags, ready-mix is cheaper and far less work.
Depth by use
| Use | Depth | Why |
|---|---|---|
| Mulch, established beds | 2–3 in | Deeper than 3 in holds water against stems and starves roots of air. |
| Mulch, new beds over bare soil | 3–4 in | The extra inch is what suppresses weeds for a season. |
| Topsoil over an existing lawn | 0.25–0.5 in | Any more and the grass underneath is smothered rather than fed. |
| Topsoil for a new lawn | 4–6 in | Roots need the depth once, at the start; it cannot be added later. |
| Gravel walkway | 2–4 in | Over a compacted base, not over soil. |
| Gravel driveway, surface course | 3–4 in | Over 6 to 8 in of compacted base. |
| Gravel driveway, full build | 8–12 in | Base and surface together, laid and compacted in layers. |
| Concrete patio or walkway | 4 in | Four inches is the ordinary residential slab. Follow the specification for anything carrying a vehicle. |
How much extra to order
| Reason | Add | Note |
|---|---|---|
| Compaction, crushed stone | 20% | Six inches loose settles to about five. Order for the finished depth. |
| Settling, mulch and soil | 10–15% | Organic material shrinks as it breaks down over the first season. |
| Spillage and uneven ground | 5–10% | A hole is never the rectangle it was measured as. |
| Concrete, sub-base variation | 5–10% | A slab poured half an inch deep over 200 sq ft is a third of a yard nobody ordered. |
What does it cost?
Typical price is $3–$10 per sq ft. Pavers only. Installed patios run several times this because the excavation and the compacted base are most of the labour.
| Item | Typical price |
|---|---|
| Concrete pavers | $3–$7 per sq ft |
| Clay brick pavers | $5–$10 per sq ft |
| Paver base gravel | $20–$55 per ton |
| Patio installed | $12–$30 per sq ft |
Price ranges as of 2026. Materials pricing moves — treat these as a sanity check on a quote, not as a quote.
The formula
- Area to cover
20 * 12 - Each paver with its joint
((8 + 0.125) * (4 + 0.125)) / 144 - Pavers before cuts
240 / 0.2327474 - Pavers to buy
ceil(1031.1608 * (1 + 10 / 100)) - Gravel base
(240 * (4 / 12)) / 27 - Bedding sand at 1 in
(240 * (1 / 12)) / 27 - Edge restraint
2 * (20 + 12)
Source: Interlocking Concrete Pavement Institute, ASTM C936 — solid concrete interlocking paving units
Questions people actually ask
- How many pavers per square foot?
- For an 8 × 4 in paver with an eighth-inch joint, 4.30 — because the joint makes each one occupy 0.2327 sq ft rather than the 0.2222 its face measures. Ignoring the joint over-orders by about 5%, which on a 240 sq ft patio is 49 pavers.
- How much extra should I buy for cuts?
- Five per cent for a rectangle laid running bond, ten for anything with a curve, fifteen for herringbone or a 45-degree layout — every diagonal course ends in two offcuts and only one of them is usable.
- What goes under the pavers?
- Four to six inches of compacted crushed base for a patio, six to eight where a car parks, then exactly one inch of bedding sand screeded flat. The bedding layer is not a levelling course: laying it thicker to fix a low base is the commonest reason a patio ruts.
- Do I need edge restraint?
- Yes, on every free edge. Sand-set pavers spread sideways under load, and the restraint is what stops the outer course creeping. The perimeter figure above is the full outline — subtract any side that runs against a wall or a kerb.
Related
- Gravel & Aggregate CalculatorCubic yards and tons of gravel, sand, limestone or topsoil for an area at a given depth.
- Square Footage CalculatorSquare footage of a room, wall, border, gable end, ring or triangle from feet-and-inches measurements, with a waste factor and the cost.
- Concrete CalculatorCubic yards of concrete for a slab, round pad, footing, column, wall or stairs, with bag counts and cost.
- Sod CalculatorRolls and pallets of sod for a lawn, from the area and the roll size the farm cuts, with the waste a shaped lawn actually needs.
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