Paver Calculator — pavers, base, bedding sand and edging

The paver calculator above prices a segmental paving job as the layered build-up it actually is. It returns paver count, compacted base aggregate in tons, bedding sand volume, linear feet of edge restraint and bags of joint sand, then adds the whole thing up. Most paver tools stop at the paver count, which is the cheapest and least risky part of the job.

Arb Digital publishes this in a free construction estimating set. The reason it goes below the surface is that a paved area fails from the bottom up. A patio laid on an inadequate base will settle, rut and open its joints regardless of how good the pavers are, so a bill of materials that leaves out the base is not a bill of materials for a patio.

What This Paver Calculator Does

It works out how many square feet one paver covers including its joint, divides the area by that figure, applies a pattern-dependent waste allowance and rounds up to whole units. Separately it computes the volume of the compacted aggregate base and converts it to tons at a density you can see and edit, computes the bedding sand volume at your screeded depth, derives the perimeter for edge restraint and converts the paving area into bags of joint sand at the coverage printed on the bag.

That layering is the boundary between this and our tile calculator, which covers tile bonded to a prepared substrate with adhesive and grout — no base course, no bedding sand, no edge restraint, and a completely different failure mode. If you only need the surface area, the square footage calculator is quicker, and for bulk aggregate on its own the gravel calculator handles any material and depth.

How to Use It

1. Enter the area. Rectangle, circle or a known area you have already measured. The perimeter for edging is derived from the shape you choose.
2. Enter the real paver size and joint width. Use the moulded dimensions, not the nominal name. Joint width changes the coverage of every single unit, so it changes the count.
3. Pick the laying pattern. This sets the waste allowance, because a 45-degree herringbone produces two angled offcuts on every perimeter unit while a running bond mostly produces reusable halves.
4. Set base and bedding depths. Bedding is screeded to a nominal one inch. Base depth comes from the pavement design for your traffic and subgrade.
5. Deduct restrained edges. Where the paving runs up against a house wall or an existing kerb it does not need edge restraint, so enter that length to remove it from the edging figure.

The Formula / How It's Calculated

Pavers first. One unit occupies (paver length + joint) × (paver width + joint), converted to square feet by dividing by 144. Raw count is area ÷ that figure, and the order figure is ceil(raw × (1 + waste)). Base aggregate is area × base depth converted to cubic yards, then multiplied by density and divided by 2,000 for tons. Bedding sand is area × bedding depth in the same way. Edge restraint is the perimeter less any restrained edge. Joint sand is ceil(area ÷ coverage per bag).

The specification figures behind the defaults come from the CMHA Guide Specification for the Construction of Interlocking Concrete Pavement, published by the Concrete Masonry and Hardscapes Association, formerly the Interlocking Concrete Pavement Institute. It calls for bedding sand screeded to a nominal 1 inch (25 mm), specifies bedding sand conforming to ASTM C 33 gradations while explicitly prohibiting stone dust and limestone screenings, sets joint widths between 1/16 and 3/16 inch (2 to 5 mm) with no more than five percent exceeding 1/4 inch, requires base compaction to not less than 98 percent Proctor density to ASTM D 698 for pedestrian areas and residential driveways, and holds the base surface to a tolerance of plus or minus 3/8 inch over a 10 foot straight edge before the sand goes down. The default base density of 3,700 pounds per cubic yard is the compacted gravel base figure from Exhibit 620-1 of the WSDOT Design Manual, Chapter 620.

The Joint Is Part of the Paver

An 8 by 4 inch paver does not cover 32 square inches. With a 1/8 inch joint it covers 8.125 by 4.125, which is 33.5 square inches — about 4.7 percent more. Over a 240 square foot patio that difference is roughly fifty pavers, and it works in your favour: ignoring the joint makes you over-order. Ignore it in the other direction, on a wide-jointed permeable system where joints can be far larger, and the error stops being small.

The joint is not decorative. Interlocking concrete pavement transfers load between units through the joints, which is why the specification puts limits on how wide they may be and why the joint sand has to be installed and compacted properly rather than swept in as an afterthought. A paved surface with empty joints has lost the mechanism that makes it a pavement rather than a collection of individual blocks, and it will start to rock and spread under traffic.

Pattern Decides Waste, Not the Shape of the Patio

The pattern waste allowance is not padding. A running bond laid parallel to a rectangular edge produces mostly half-unit cuts, and half units are usually reusable at the opposite edge, so five percent is realistic. A 45-degree herringbone produces a triangular offcut at every perimeter unit, and while some pairs match up, many do not — ten percent is a fair allowance and complex outlines justify more.

Curves are the expensive case. Every unit meeting a curved edge has to be cut individually to a unique angle, and the offcut is scrap. A circular patio or a walkway with sweeping edges can easily run beyond fifteen percent. The trade-off is worth understanding before the design is fixed: a curved edge is a design decision with a material cost attached, and on a small job the extra pavers can outweigh the aesthetic benefit.

Herringbone is not just decorative either. Laid at 45 degrees to the direction of traffic it resists the creeping horizontal movement that vehicle braking and turning imposes on a pavement, which is why it appears so often on driveways and in heavy-duty applications. The extra waste buys structural performance, not just a look.

Base Depth Is the Decision That Costs Money Later

Base aggregate is usually the single heaviest item in a paving job, and it is the one people trim when the budget tightens. That is the wrong item to trim. The pavers do not carry the load; the compacted base does, spreading wheel and foot loads out over the subgrade beneath. Take depth out of the base and the load concentrates, the subgrade deforms, and the surface follows it down.

Depth requirements scale with what the surface carries and what it sits on. A pedestrian patio on well-drained sandy subgrade needs far less than a driveway on clay. In cold climates, frost-susceptible subgrade adds another requirement entirely, because the base has to be thick and free-draining enough to keep water away from frost-susceptible material. This tool does not choose a depth. It costs the depth you enter, and the depth itself comes from the pavement design and the paver manufacturer's specification. Local code and a qualified professional govern that decision.

Compaction is not optional either. The specification calls for the base to reach at least 98 percent of Proctor density for pedestrian areas and residential driveways. Loose aggregate spread to the right depth is not a base — it is a base waiting to settle by an inch, which is exactly the amount of settlement that ruins a patio.

Edge Restraint: the Cheapest Part, the Most Common Failure

Segmental paving spreads sideways under load. Without something holding the perimeter, the outer courses migrate outwards, the joints open, the sand washes out and the failure works its way inwards from the edge. Edge restraint costs a small fraction of the job and prevents the most common way a DIY patio goes wrong.

The tool calculates the perimeter and lets you deduct any edge that is already restrained — a house wall, an existing kerb, a retaining wall. What remains is what needs a restraint installed, and it must be spiked into the compacted base, not into the bedding sand. Fixing it into sand achieves nothing, because the sand moves with the pavers.

Reading the Raw Count Against the Purchasable Count

Both figures are on screen. The raw count is the honest coverage requirement. The order count is that number after pattern waste, rounded up. It is worth ordering slightly beyond even the waste figure on a paver job for a reason that does not apply to most materials: concrete pavers are made in batches, and colour varies between batches. Running short and returning for one more pallet often means a visibly different colour in the last two square metres of a patio.

Related to this, professional installers pull units from three or four pallets at once rather than emptying one pallet before opening the next. Batch variation exists even within an order, and blending across pallets distributes it invisibly instead of leaving a stripe across the paving.

Common Mistakes to Avoid

• Ignoring the joint width — the joint is part of every unit's coverage, and on wide-jointed systems it changes the count materially.
• Using stone dust or screenings as bedding — the specification requires a washed concrete sand gradation and explicitly prohibits stone dust and limestone screenings.
• Screeding the bedding sand thicker to level a bad base — bedding is a nominal one inch, and a deep sand layer consolidates unevenly and ruts.
• Spiking edge restraint into the sand — restraint has to be fixed into the compacted base or it moves with the paving it is meant to hold.
• Ordering exactly the calculated count — batch colour variation makes a top-up pallet visibly different, so the waste allowance is doing two jobs.

Related Free Tools From Arb Digital

Pair this with the gravel calculator to price the base and bedding aggregate against your supplier's own density, the concrete calculator if any of the edging is a poured kerb, the tile calculator for bonded interior work, the square footage calculator for an awkward outline and the cubic yard calculator for volume conversions. The free online tools hub lists every calculator we publish.

Frequently Asked Questions

This tool produces material estimates only. Base thickness, compaction, drainage and pavement design are governed by the project specification and local code, and must be confirmed by a qualified professional before construction.