Paver Sand Calculator

A paver surface uses sand in two places, and people often mix them up. The bedding layer is the sand under the pavers. It levels the surface and lets each paver settle into place when the plate compactor goes over. The joint sand is swept into the gaps afterwards to lock the pavers together. The calculator can work out either one, or both together.

The bedding layer is area times depth. Measure the length and width of the surface in feet, multiply them, and multiply by the depth in feet, which is the depth in inches divided by 12. For 100 square feet at 1 inch, that is 8.33 cubic feet. Divide by 27 for cubic yards: 0.309.

The joint sand comes from the geometry of the pavers. The calculator looks at the cell each paver occupies, its length plus the joint by its width plus the joint, and takes away the paver. What is left is the joint, and it multiplies by the joint depth, which is the paver thickness.

Both volumes turn into weight with a density, 97 pounds per cubic foot for loose dry sand, and the order adds your extra percentage. The result shows tons, cubic yards, bags and cost. If you also need the paver count, it is in the results too, because it comes from the same cell size.

The guidance here comes from the Interlocking Concrete Pavement Institute, now part of the Concrete Masonry and Hardscapes Association. The bedding layer is screeded to a nominal 1 inch, or 25 mm. ICPI Tech Spec 10 gives the working range as 1 to 1 1/2 inches uncompacted, with a consistent thickness. That is why the calculator starts at 1 inch.

The sand matters as much as the depth. Bedding sand should meet the grading of ASTM C33, the concrete sand grading. Do not use mason sand for bedding, because it drains slowly and is unstable. Do not use stone dust or screenings either, because they have too many fines. The last table on this page sets out which sand goes where.

A common mistake is using the sand to fix a bumpy base. The ICPI guidance says not to. Low spots in the base show through in the finished surface. Fix them with base material and compact, then screed the sand over a flat base. The sand layer should be even, so the pavers settle evenly.

A thicker sand layer is not a better one. It settles more under traffic and leaves ruts. If you find yourself wanting 2 inches of sand, the base probably needs work. For the weight and cost of a deeper layer, the table of depths shows how fast the quantity grows.

The sand is only a leveling layer. The strength of a paver surface comes from the compacted aggregate base below it. ICPI gives a minimum compacted base of 4 to 6 inches for walks and patios, 6 to 8 inches for driveways, and 8 to 12 inches for streets. The right thickness depends on the soil, drainage, climate and traffic, and a design professional should review heavy-duty jobs.

The base is compacted in lifts, usually 4 to 6 inches at a time with a plate compactor, and finished smooth to within 3/8 inch over a 10 foot straightedge. A flat base is what makes a 1 inch layer of sand enough.

This calculator covers the sand. For the base stone, use the Gravel Calculator or the Stone Calculator with the base depth, remembering that compacted base needs more weight than loose stone. Ask your supplier for the compacted weight per cubic yard.

On a driveway, the base is the biggest material order by far, so measure it carefully. The bedding sand is a small fraction of it, and it should never be used to make up the difference.

Joint sand is the sand swept into the gaps. ICPI describes a dry sand swept and compacted into the joints until they are full. It can be the bedding sand, or a finer mason sand to ASTM C144, which is easier to sweep in. Joints should be a consistent 1/16 to 3/16 inch wide.

Polymeric sand is joint sand with binders. It hardens when wet and resists washout, ants and weeds. Manufacturer data sheets set limits, such as a minimum joint width of about 2 mm and a depth of 32 mm, dry pavers and no rain right after install. The calculator estimates the sand needed to fill the joints. Your bag label gives the product's own coverage, and it should win.

The quantity depends mostly on the joint width, the paver size and the paver thickness. A 4 × 8 in paver with 1/8 in joints has joints equal to 4.52 percent of the surface. At 1/16 in it is 2.30 percent, and at 3/16 in it is 6.67 percent. Small pavers have more joint per square foot, and large slabs have less.

The joint fill box lets you fill part of the depth if a product calls for it. Leave it at 100 percent for a full fill, and keep the extra percentage, because sand is lost in sweeping and settles after the first rain.

The question people ask most is how far a bag goes. The calculator answers it for your layout: the square feet covered by one bag equals the bag weight divided by the pounds of sand each square foot needs. For 4 × 8 in pavers at 1/8 in joints that is 58 square feet per 50 lb bag.

Three things move the number. Wider joints use more sand, so coverage falls. Thicker pavers have deeper joints, so coverage falls. Larger pavers have fewer joints, so coverage rises. A 12 × 12 in paver at 1/8 in joints has a 50 lb bag covering 127 square feet, over twice the 4 × 8 figure.

Product labels often show a range, because the real joint is never perfectly uniform and some sand is lost. Treat the calculator figure as the fill volume and the label as the product's practical coverage. If the label's coverage is lower, buy by the label. If you are using plain sand rather than polymeric, buy by the calculator.

The tables on this page show coverage by joint width and by paver size, so you can see how much a change in either one matters before you buy.

Because the paver count uses the same cell size, the calculator gives it too. Each paver, with its joint, occupies (length + joint) times (width + joint). Divide the area by that cell to get the count. For 12 × 12 in pavers with 1/8 in joints, one paver uses 1.021 square feet, so 100 square feet takes 97.9 pavers. Round up to 98, then add your extra for cuts.

Cuts are the main reason to order extra. Curves, edges and angled corners all produce offcuts that cannot be reused. Ten percent is normal for a plain rectangle. Use 15 percent or more for circles or patterns with many cuts. Keep a few spare pavers after the job for repairs, because the colour of a later batch may differ.

For small bricks, the same sum applies in metres. A 200 × 100 mm brick with 3 mm joints takes 0.203 × 0.103 m, so 500 of them cover 10.45 square metres. Without joints, they would cover exactly 10.0. The table of bricks and area gives the figures for other counts.

The paver count in the results is only available when the sand mode includes joints, because that is when the paver size is used.

In metric, lengths are in metres, the bedding depth in centimetres and the paver sizes in millimetres. The default density is 1,555 kilograms per cubic metre, the dry sand figure of 97 pounds per cubic foot. One square metre at 25 mm needs 38.9 kilograms, which is 1.55 bags of 25 kg.

For small jobs, bags make sense. A patio of 20 square metres needs 778 kilograms, which is 35 bags of 25 kg with 10 percent extra. At that size many suppliers offer bulk bags of about a tonne, or a loose delivery by the cubic metre, which is cheaper and easier to move.

Keep the sand dry. Damp sand is fine for screeding, but a wet pile weighs more, about 119 pounds per cubic foot against 97 dry, so a delivery ticket can be heavier than the calculator suggests. Cover the pile before rain and spread the bedding sand on the day you lay the pavers.

The price box holds a placeholder. Put in your own quote per ton, tonne, cubic yard or cubic metre. The cost is material only, with no delivery or tax.

The results are estimates. They assume a flat base, an exact bedding depth, regular pavers and a loose dry density. Sand compacts under the plate, joints are never perfectly uniform and the base can vary, so the extra percentage is there for a reason. Follow the paver maker's instructions and your local requirements, and have a qualified contractor review driveways and other heavy-duty areas.

For the stone below the sand, use the Gravel Calculator or the Stone Calculator. If your surface is a wall or a block project instead, the CMU Block Calculator counts the units. Measure twice, buy a little extra, and keep the receipt for any sand you may return.