Paver Base Calculator — aggregate for a paver patio or driveway
Work out the aggregate for both the compacted base layer and the bedding course under pavers — calculated separately, because they are placed at very different thicknesses.
A paver installation has two aggregate layers: a thick compacted base that carries the load, and a thin screeded bedding course that the pavers sit on. They are placed at very different thicknesses and are easy to confuse, so this calculator lets you price each one.
Use the depth presets to jump to a typical base thickness, or enter your own. If you are calculating the bedding course only, set the depth to 1 inch — and note that bedding sand is screeded rather than compacted, so the compacted density we apply slightly over-states it, which is the safe direction for ordering.
The density range comes from Wisconsin DOT aggregate research and Iowa DOT estimating figures, both linked below. The compaction state is stated explicitly, because loose and compacted aggregate differ by more than 20% in volume.
A worked example you can check by hand
A 20 ft × 10 ft area at 2 in deep,
with a 5% waste allowance:
We do not use a hidden "magic number". Here is the entire calculation:
volume = area × depth
volume_with_waste = volume × (1 + waste%)
weight = volume_with_waste × density
Why a range, not one number? Bulk material density changes with
moisture, gradation and compaction. Publishing a single figure would be falsely precise, so we publish
the range our sources support — and we show you exactly where each number comes from.
Why we state the state. This material is only published at one
placement state, so there is nothing to choose — but we say which one it is, because loose and compacted
material differ by 27–60% in volume and most calculators never tell you which they used.
Crusher run / dense-graded aggregate base, compacted
How we chose the typical value. WisDOT's research-recommended range for 3/4 in dense-graded base is 1.78–1.98 short ton/yd³; the midpoint is 1.88 t/yd³. We set the typical at 1.9 t/yd³ (= 140.7 lb/ft³), which is also exactly Iowa DOT's Class "A" crushed stone estimating value of 140 pcf. Two independent state DOTs agree.
Limits of this constant
Compacted in-place density. If you are ordering loose material by volume, the same tonnage occupies noticeably more volume — see the state selector.
WisDOT also publishes a wider statewide empirical band (1.75–2.10 t/yd³) used for contract bidding. We use the narrower research range and say so.
This calculator is only valid under these assumptions. If any of them do not match your project,
treat the result as a rough guide and get a quote from your supplier.
The base layer and the bedding course are calculated as two separate layers at their own thicknesses, then added.
The base aggregate is compacted crusher run or dense-graded base; the bedding course is screeded, not compacted, but is calculated here with the same compacted density, which slightly over-estimates it.
The area is a simple rectangle and the surface is flat. Slopes and steps need separate calculations.
No allowance for edge restraints, geotextile, joint sand or the pavers themselves.
Paver thickness is not part of this calculation — it does not affect how much base aggregate you need.
Frequently asked questions
How much base do I need under pavers?
A 4 inch compacted base is standard for a pedestrian patio on firm ground, 6 inches for a driveway carrying cars, and 8 inches or more where heavy vehicles will park. On top of that goes about 1 inch of bedding sand or fine aggregate for screeding.
Should I calculate the base and the bedding separately?
Yes, if you want an accurate order. The base is typically 4 to 8 inches and is compacted; the bedding course is about 1 inch and is screeded. Adding them into one figure hides the fact that they behave differently and are sometimes different materials.
How many tons of base for a 300 square foot patio?
At 4 inches compacted with an 8% allowance, a 300 square foot patio needs roughly 11 cubic yards, or about 21 short tons, of crusher run. The calculator shows the exact figure and the range for your own dimensions.
Does paver thickness change how much base I need?
No. Paver thickness affects the finished height and the edge restraint, not the volume of aggregate underneath. This calculator therefore ignores it.