How it works
The calculator finds the area, multiplies it by each layer’s depth, adds the compaction allowance to the base, and – if you enter densities – converts the volumes to weight.
Area = Length × Width
Base, compacted = Area × Base depth
Base to order = Base, compacted × (1 + Compaction ÷ 100)
Bedding sand = Area × Sand depth
Weight = Volume to order × Weight per volume
Digging depth = Base depth + Sand depth + Paver thickness
Units are converted internally, so you can enter the patio in feet, the depths in inches and the densities in tons per cubic yard or pounds per cubic foot. One cubic yard is 27 cubic feet.
The layers under a paver patio
An interlocking paver patio is a stack of layers. From the bottom: the compacted soil subgrade, a compacted aggregate base (crushed stone), a thin layer of bedding sand, and the pavers. The Concrete Masonry & Hardscapes Association (CMHA, which includes the former Interlocking Concrete Pavement Institute) describes this structure in its construction guide PAV-TEC-002, and the example values here come from it: a 4 in (100 mm) compacted base, the minimum it gives for patios and pedestrian areas over well-drained soils, and a 1 in (25 mm) bedding layer.
The paver calculator counts pavers. This page answers the other half of the order: how much base stone and sand to have delivered.
Base depth depends on the site
The base carries the load and keeps the surface flat. CMHA says its thickness is determined by traffic, soil type, drainage, moisture and climate: at least 4 in (100 mm) for sidewalks, patios and pedestrian areas over well-drained soils, at least 6 in (150 mm) for residential driveways, and thicker bases in colder climates and on continually wet or weak soils. This calculator doesn’t decide the depth for your site – enter the depth from your paver manufacturer’s guide or your installer, and it gives you the quantities.
Compaction allowance
Base stone is spread and compacted in lifts; CMHA describes 4 to 6 in (100 to 150 mm) lifts with a plate compactor. Loose stone gets thinner when it is compacted, so the volume you order has to be larger than the finished layer. How much larger depends on the material and its grading, so ask your supplier and enter the percentage. With an empty or 0 allowance you see the compacted volume in place.
Bedding sand
Bedding sand is screeded over the compacted base to a nominal 1 in (25 mm) and is not compacted until the pavers are vibrated into it. CMHA asks for concrete sand (ASTM C33 or CSA A23.1) and says masonry sand, limestone screenings and stone dust should not be used. It also warns against using the sand to make up for an uneven base. The sand calculator works out bagged sand if you prefer bags.
Weight and ordering
Bulk base stone and sand are usually sold by the ton. The weight per cubic yard differs between materials – a Wisconsin DOT study found compacted aggregate at about 1.5–2.2 tons per cubic yard depending on gradation, with loose material weighing less – so use the figure your supplier gives for the exact product and enter it for each layer.
Digging depth
Add the base, the bedding sand and the paver thickness to see how far below the finished surface to excavate. For 2 3/8 in pavers on 1 in of sand and a 4 in base, that is 7 3/8 in. Allow for the slope you need for drainage and for any subbase your installer specifies.
Worked example
Inputs
- Measure by
- Patio length × width
- Patio length
- 12 ft
- Patio width
- 10 ft
- Base depth (compacted)
- 4 in
- Bedding sand depth
- 1 in
- Paver thickness (optional)
- 2 3/8 in
Result
- Paved area
- 120 sq ft
- Base volume, compacted in place
- 1.48 cu yd (40 cu ft)
- Base stone to order
- 1.48 cu yd (40 cu ft)
- Bedding sand
- 0.37 cu yd (10 cu ft)
- Digging depth below finished surface
- 7.38 in
Common mistakes
- Ordering the compacted base volume as loose stone. Base material gets thinner when it is compacted, so you need more loose stone than the finished layer – enter your supplier’s compaction allowance.
- Making the bedding sand thicker to hide an uneven base. CMHA says unevenness in the base must be fixed before the sand is placed, because it reflects through to the surface over time.
- Using stone dust or mason sand for bedding. CMHA asks for concrete sand (ASTM C33 or CSA A23.1) and says masonry sand, limestone screenings and stone dust should not be used.
- Using a patio depth for a driveway. CMHA’s minimum for residential driveways on well-drained soils is 6 in (150 mm), more than for patios.
- Mixing up short tons and metric tonnes. A US short ton is 2,000 lb, a metric tonne is 1,000 kg.
Assumptions and limits
- The area is a rectangle, or you have entered its total area, and both layers have an even depth everywhere.
- Base to order = compacted volume × (1 + compaction allowance). The bedding sand is screeded and is not compacted before the pavers go down, so no allowance is added to it.
- Weights are the volumes to order × the densities you enter. No density is assumed.
- Digging depth = base + bedding sand + paver thickness, measured down from the finished paver surface. Slope for drainage, any subbase and geotextile are not included.
- The pavers themselves, joint sand and edge restraints are not counted here – the paver calculator counts the pavers.
Frequently asked questions
How deep should a paver base be?
It depends on use, soil, drainage and climate. CMHA’s construction guide gives a minimum compacted base of 4 in (100 mm) for sidewalks, patios and pedestrian areas over well-drained soils and 6 in (150 mm) for residential driveways, with thicker bases in cold climates and on wet or weak soils. Follow your paver manufacturer or a local professional for your site.
How much sand goes under pavers?
CMHA says bedding sand should be spread and screeded to an uncompacted nominal 1 in (25 mm). For a 120 sq ft patio that is 10 cubic feet of sand.
How much extra base stone should I order for compaction?
It depends on the material and how loose it is delivered, so ask your supplier and enter the figure under Compaction allowance. The calculator does not assume one.
Is this the same as the paver calculator?
No. The paver calculator counts the pavers for an area. This calculator works out the layers underneath – the compacted base and the bedding sand – with weights and a digging depth.
Do I need landscape fabric under the base?
CMHA describes geotextile under the base as optional – used where soil stays saturated, where there is freeze and thaw, or over clay and silty soils. The landscape fabric calculator counts rolls if you use it.
Sources
- PAV-TEC-002-22 – Construction of Interlocking Concrete Pavements — Concrete Masonry & Hardscapes Association (formerly ICPI). "Sidewalks, patios and pedestrian areas should have a minimum base thickness (after compaction) of 4 in. (100 mm) over well-drained soils"; "Bedding sand should be spread and screeded to an uncompacted nominal 1 in. (25 mm) thickness."
- Aggregate unit weights – WisDOT research report 0092-22-05 — Wisconsin Department of Transportation. Compacted aggregate unit weights of about 1.5–2.2 tons per cubic yard depending on gradation; loose material weighs less.
- SAKRETE Multi-Purpose Sand – product data sheet — King Packaged Materials Company (Sika Canada). "25 KG (55 lb) yields approximately" 0.0175 m³ not compacted and 0.015 m³ compacted (metric bag default 17.5 L).
- NIST Handbook 44, Appendix C – General Tables of Units of Measurement — National Institute of Standards and Technology. Exact unit definitions: 1 in = 2.54 cm, 1 yd³ = 27 ft³, 1 US gal = 231 in³, 1 lb = 0.45359237 kg.
Method reviewed November 4, 2026