Separate the layers below a paved surface
A paved patio can have a compacted aggregate base with a thinner bedding layer above it. Those layers serve different purposes and are ordered as different materials. Measure the prepared rectangle that needs base material; if your design extends the base beyond the visible pavers, include that extension in the dimensions. Enter the finished compacted base depth, not the entire excavation depth containing paver thickness.
Convert compacted volume into a loose order
Compacted base = area × base depth; loose aggregate = compacted base × supplier factorA loose delivery can occupy more space than the same aggregate after compaction. The editable ratio represents loose volume divided by finished compacted volume. A factor of 1.2 means ordering 1.2 units of loose material for each unit of compacted base, not losing twenty percent of the delivery. The example factor is arithmetic input rather than a universal material property. Obtain an appropriate value for the selected aggregate, moisture conditions and compaction method.
A five by four metre patio base
A 20 square metre prepared area with a 15 centimetre compacted base contains 3 cubic metres of compacted aggregate. Multiplying by a loose-to-compacted factor of 1.2 produces a 3.6 cubic metre order, approximately 4.7087 cubic yards. A separate 3 centimetre bedding layer contains 0.6 cubic metres of sand. Sand is not multiplied by the aggregate factor because it is a distinct material with its own placement requirements.
Set the design before calculating the takeoff
Required depth depends on loading, subgrade, drainage, climate and the selected paving system. This page does not choose a base depth or a compaction specification. For a sloping formation, use the actual average layer thickness or divide the site into measured sections. The volume output does not become tonnes without the supplier's density: bulk mass varies with aggregate type and moisture. Jointing sand, edging, geotextile and pavers themselves are separate quantities. A bedding depth of zero is allowed when that layer is absent from your design. Check excavation levels and delivery access before ordering, and avoid applying another compaction allowance if the supplier has already quoted the required loose quantity for your finished base.
Frequently asked questions
Is paver thickness included?
No. Enter the compacted aggregate and bedding depths separately. Paver thickness affects excavation but is not part of either material volume.
Why must the aggregate factor be at least one?
The model assumes loose aggregate occupies at least the compacted volume. A factor below one reverses that assumption and is rejected.
Can I get tonnes from this result?
Only with the appropriate bulk density. Ask the supplier to convert the loose order volume to mass for the selected material.
Is bedding sand compacted by the same factor?
No. Its displayed volume is geometric and separate. Use the bedding product's own placement and ordering instructions.
What depth should a driveway use?
This worksheet does not design pavement layers. Obtain a depth appropriate to vehicle loads, ground conditions and the paving system.
Last reviewed: 2026-10-05 · How we calculate