Paver and patio calculator guide
The calculator above turns a patio, walkway or driveway into the four quantities every paver job actually needs — the pavers themselves, the crushed-stone base under them, the bedding sand they sit on, and the polymeric sand that fills the joints — plus an optional cost, in metric or imperial, all in your browser.
The guide below explains how to work out pavers from the area and paver size, why the laying pattern changes how many spares you need, how much base gravel and bedding sand a compacted layer really takes, how joint sand is sold by coverage per bag, and worked examples you can reproduce by hand.
How many pavers do I need?
To work out how many pavers you need, divide the patio area by the area of one paver, then add an allowance for cuts and breakages that depends on the laying pattern. In short: pavers = area ÷ paver area × (1 + waste), rounded up to whole pavers.
A nominal 4 × 8 in (100 × 200 mm) paver covers about 0.02 m² (0.22 ft²), so a 20 m² (215 ft²) patio needs roughly 1,000 pavers before waste and about 1,050 in a running-bond layout with 5% waste. The calculator does every step as you type, sets the waste from the pattern you choose, and rounds up.
Enter the patio as a length and width — never a raw area unless you already know it — so a unit mix-up can't silently change your order, and switch between metric and imperial at any time.
Estimate your paver job in seven steps
- Choose unitsPick metric (m, mm, kg) or imperial (ft, in, lb); every value converts when you switch.
- Enter the patio sizeType the patio length and width, or switch to direct-area entry if you already know the area.
- Set the paver and patternChoose a nominal paver size or enter custom dimensions, then pick the laying pattern, which sets the waste allowance.
- Set the base and beddingPick the application to seed the base depth, choose the base and bedding materials, and adjust the loose depths if needed.
- Set the joint sandEnter the joint width and confirm the coverage per bag against your product so the joint-sand bags are accurate.
- Add prices (optional)Enter per-paver, base, bedding and joint-sand prices to turn the quantities into a total project cost.
- Read the results, export or printCheck the pavers, base, bedding, joint sand and dig depth, then export to CSV or print the shopping list.
Base gravel and bedding sand
Pavers are only as good as what's under them. Industry guidance (ICPI/CMHA) puts a compacted crushed-stone base of about 4 in (100 mm) under patios and walkways, and 6 in (150 mm) or more under a driveway, topped by roughly 1 in (25 mm) of screeded bedding sand. The calculator seeds the base depth from the application you pick and lets you edit both depths.
The depth you enter is the loose, as-delivered depth — the volume as it arrives from the supplier before it's compacted. The calculator converts that to a compacted volume, adds an order-waste allowance, and turns it into a weight in tonnes or tons and a rough bag count, using the density and compaction of the material you choose.
The base, bedding and dig-depth results come from these formulas.
Base & bedding tonnage
loose = area × depth; compacted = loose ÷ (1 + compaction); order = compacted × (1 + waste); weight = order × density- Depth is the loose, as-delivered depth in metres; density is the bulk density in kg/m³.
- Compaction and order waste are applied in turn, not added together, so the two never double-count. Bags round up from the order weight.
Excavation depth
dig depth = paver thickness + base depth + bedding depth- A quick guide to how deep to dig out before you start; add a little for screeding and fall.
- With a 2⅜ in (60 mm) paver, 4 in (100 mm) base and 1 in (25 mm) bedding that's about 7⅜ in (185 mm).
Pattern waste: why herringbone needs more
Every paver job loses some units to cuts at the edges and around obstacles, plus the odd breakage. How much you lose depends mostly on the laying pattern: a straight running or stack bond wastes little, while a 45° herringbone cuts many pavers at the perimeter and needs the most spares.
The calculator sets the waste allowance from the pattern you choose, using the typical figures below, and you can override it for a tricky shape. The gallery shows how each pattern lays out.
| Pattern | Typical waste | When it applies |
|---|---|---|
| Running bond | 5% | Rows offset by a half; the simplest, lowest-waste layout. |
| Stack bond | 5% | Pavers stacked in a straight grid; similar low waste to running bond. |
| Basketweave | 8% | Alternating horizontal and vertical pairs; a little more cutting at the edges. |
| Herringbone 90° | 10% | Interlocking zig-zag square to the edges; more perimeter cuts. |
| Herringbone 45° | 15% | The zig-zag turned 45°; the most cutting and the most spares. |
Each swatch is a top-down sample of the pattern, drawn by the same engine the live diagram uses.
Polymeric joint sand
Polymeric sand fills the joints between pavers and hardens to lock them in place and resist weeds and ants. It's sold by coverage per bag, and that coverage depends heavily on your joint width — a bag stretches much further across narrow joints than wide ones.
The calculator keys a typical coverage-per-bag figure off your joint width and divides the patio area by it to get whole bags. Coverage is brand-variable, so the value is editable — always check the number printed on your actual bag.
Polymeric joint sand is estimated from coverage per bag.
Joint sand bags
bags = ⌈ patio area ÷ coverage per bag ⌉- Coverage per bag depends on joint width: roughly 80 ft² (7.4 m²) at ⅛ in, 50 ft² (4.6 m²) at ¼ in and 35 ft² (3.3 m²) at ⅜ in per 50 lb (25 kg) bag.
- These are typical figures — coverage varies by brand, so verify against your product's bag before buying.
What a paver base looks like in section
Cut through a finished patio and you see four layers plus an edge. From the bottom up: the compacted subgrade (native soil), the crushed-stone base that carries the load, a thin bedding-sand layer that the pavers are screeded onto, the pavers themselves, and polymeric sand swept into the joints. An edge restraint around the perimeter stops the whole assembly from spreading.
This cross-section is why the calculator estimates base gravel, bedding sand and joint sand alongside the pavers — each layer is a separate material you have to buy.
Worked examples
Each example reproduces what the calculator returns, so you can check the method by hand. Figures use the calculator's defaults — 4 × 8 in (100 × 200 mm) pavers, patio application (4 in base, 1 in bedding), 8% aggregate order waste, ⅜ in joints — unless stated.
Each example reproduces the calculator's output for the given inputs.
Pavers for a 5 m × 4 m patio
Metric · running bond- Given
- Patio 5 m × 4 m = 20 m²
- Paver 100 × 200 mm (0.02 m²), running bond (5% waste)
- Patio base 100 mm, bedding 25 mm, 8% order waste, ⅜ in joints
- Formula
pavers = area ÷ paver area × (1 + waste)- Steps
- Pavers to cover: 20 ÷ 0.02 = 1,000
- With 5% waste: 1,000 × 1.05 = 1,050 pavers
- Base: loose 20 × 0.1 = 2.0 m³ ÷ 1.12 × 1.08 × 1,600 ≈ 3.1 t
- Bedding: loose 20 × 0.025 = 0.5 m³ ÷ 1.12 × 1.08 × 1,600 ≈ 0.77 t
- Joint sand: ⌈ 20 ÷ 3.3 ⌉ = 7 bags
- Result
- Buy 1,050 pavers, about 3.1 t base, 0.77 t bedding sand and 7 bags of joint sand
Pavers for a 16 × 12 ft patio
Imperial · running bond- Given
- Patio 16 ft × 12 ft = 192 ft²
- Paver 4 × 8 in (0.22 ft²), running bond (5% waste)
- ⅜ in joints, 2⅜ in pavers, 4 in base, 1 in bedding
- Formula
pavers = area ÷ paver area × (1 + waste)- Steps
- Pavers to cover: 192 ÷ 0.222 = 864
- With 5% waste: 864 × 1.05 = 907.2 → 908 pavers
- Joint sand: ⌈ 192 ÷ 35 ⌉ = 6 bags
- Dig depth: 2⅜ + 4 + 1 = 7⅜ in
- Result
- Buy 908 pavers and 6 bags of joint sand, and dig out about 7⅜ in
Same patio, laid 45° herringbone
Metric · herringbone 45°- Given
- Patio 5 m × 4 m = 20 m²
- Paver 100 × 200 mm (0.02 m²)
- Herringbone 45° (15% waste)
- Formula
pavers = area ÷ paver area × (1 + waste)- Steps
- Pavers to cover: 20 ÷ 0.02 = 1,000
- With 15% waste: 1,000 × 1.15 = 1,150 pavers
- Result
- Herringbone 45° needs 1,150 pavers versus 1,050 for running bond — the pattern alone adds 100
Common mistakes to avoid
Ordering by area alone. Pavers, base, bedding and joint sand each come in their own units and pack sizes — always let the calculator round each one up separately rather than eyeballing the square metres.
Using the same waste for every pattern. A running bond might lose 5%; a 45° herringbone can lose 15% or more. Match the allowance to the pattern or you'll run short on the cuts.
Entering the finished depth as the base depth. The depth is the loose, as-delivered depth before compaction — enter the compacted finished depth and you'll under-order.
Skimping on the base under a driveway. Patios and walkways want about 4 in of compacted base; vehicular driveways want 6 in or more. Pick the right application so the base depth is right.
Guessing joint-sand coverage. It swings widely with joint width and brand — read the coverage off the bag and enter it, rather than trusting a single rule of thumb.
Frequently asked questions
Short answers to the questions people most often ask about estimating pavers, base gravel, bedding sand and joint sand with this calculator.
How many pavers do I need?
Divide the patio area by the area of one paver, then add a waste allowance for cuts and breakages. In short: pavers = area ÷ paver area × (1 + waste). For a 20 m² patio with 100 × 200 mm pavers that's about 1,000 pavers, or 1,050 with 5% running-bond waste. The calculator does this as you type and rounds up to whole pavers.
How much base gravel do I need for pavers?
Industry guidance puts about 4 in (100 mm) of compacted crushed-stone base under patios and walkways, and 6 in (150 mm) or more under driveways. The calculator takes the loose delivered depth, converts it to a compacted volume, adds an order-waste allowance and multiplies by the material density to give tonnes or tons and a bag count.
How much bedding sand do I need?
Pavers are set on a screeded layer of about 1 in (25 mm) of sharp or concrete sand. The calculator computes it with the same loose-to-compacted-plus-waste chain as the base, so you get the bedding sand in tonnes or tons and rough bags alongside the base gravel.
How much polymeric sand do I need?
Polymeric joint sand is sold by coverage per bag, which depends on your joint width — roughly 80 ft² per 50 lb bag at ⅛ in joints, dropping to about 35 ft² at ⅜ in joints. The calculator divides the patio area by the coverage and rounds up to whole bags. Coverage is brand-variable, so check the bag.
How much waste should I allow for pavers?
For a running or stack bond, about 5% is typical. Basketweave needs roughly 8%, herringbone 90° about 10%, and herringbone 45° about 15% because they cut more pavers at the edges. The calculator sets a sensible default from the pattern and lets you override it for an awkward shape.
How much extra for a herringbone pattern?
Herringbone is the most cutting-intensive common layout. Allow about 10% for a 90° herringbone and 15% for a 45° herringbone, versus 5% for a straight bond. In a 20 m² patio that's the difference between 1,050 and 1,150 pavers. Select the pattern and the calculator applies the allowance automatically.
What size are standard pavers?
The most common is the 4 × 8 in (100 × 200 mm) brick paver; squares of 6 × 6, 8 × 8, 12 × 12 and up to 24 × 24 in (600 × 600 mm) are also standard, plus the 6 × 9 in rectangle. Actual sizes run slightly under nominal to leave room for a joint. The calculator has presets for each and a custom option.
How deep do I need to dig for pavers?
Dig out enough for all the layers: paver thickness + base depth + bedding depth. With a 2⅜ in (60 mm) paver, 4 in (100 mm) base and 1 in (25 mm) bedding that's about 7⅜ in (185 mm). The calculator shows this excavation depth so you know how deep to go before you start.
How many pavers are on a pallet?
It varies enormously by paver size and brand — anywhere from about 78 to 160 ft² of coverage per pallet — so there's no safe default. If you want a pallet count, switch the paver price to per-pallet and enter your supplier's pavers-per-pallet figure; otherwise buy by the individual paver.
Is the base different for a patio and a driveway?
Yes. A patio or walkway carries foot traffic and needs about 4 in (100 mm) of compacted base; a driveway carries vehicles and needs 6 in (150 mm) or more, often with thicker 3⅛ in (80 mm) pavers. Pick the application in the calculator and it seeds the right base depth, which you can still edit.
Does it work in metric and imperial?
Yes. Enter the patio in metres or feet and pavers in millimetres or inches, with base and bedding in tonnes or tons. Switch the unit toggle at any time and every input and result converts, so it suits both EU and US paving jobs.
Can I export or print the result?
Yes. Export CSV downloads the breakdown for Excel, Google Sheets or Numbers, and Print produces a clean shopping list with the pavers, base, bedding, joint sand and costs — handy to take to the supplier.
Is the calculator private?
Yes. Every calculation runs in your browser — nothing you enter is uploaded to a server. Your project is saved only in your own browser's local storage, so you can close the tab and return to it later.