About this calculator
This calculator takes off the materials for an unbound gravel or crushed-stone driveway, yard or path — no pavers (for block paving use the paving calculator). Enter the area as a rectangle or as a list of rectangular parts, then up to three layers laid bottom up:
- sub-base — the bottom, load-spreading layer (often coarse crushed stone or a sand–gravel mix);
- base — a finer, well-graded crushed stone;
- wearing course — the top layer you drive or walk on (fine gravel or crushed stone).
For each layer you get the compacted volume, the loose volume to order, its mass and the truck loads, plus geotextile rolls and edging pieces.
Formula
area = length × width (or the sum of the listed parts)
compacted volume = area × layer thickness
loose volume = compacted volume × loose-to-compacted factor / 100
mass = loose volume × loose bulk density
truck loads = max(ceil(loose volume / truck m³), ceil(mass / truck t)) per layer
geotextile = area × (1 + overlap % / 100); rolls = ceil(geotextile / roll area)
edging = 2 × length (long sides) or 2 × (length + width) (all around)
edging pieces = ceil(edging / piece length)
Worked example
A 10 × 3 m driveway: 200 mm crushed-stone sub-base, 100 mm crushed-stone base, 50 mm gravel wearing course, all with a 120% loose-to-compacted factor; 6 m³ / 10 t trucks.
area = 30 m²
sub-base: 30 × 0.20 = 6.0 m³ → × 1.2 = 7.2 m³ loose → × 1500 = 10.8 t → 2 loads
base: 30 × 0.10 = 3.0 m³ → 3.6 m³ → 5.4 t → 1 load
wearing: 30 × 0.05 = 1.5 m³ → 1.8 m³ → × 1650 = 2.97 t → 1 load
total: 12.6 m³ loose, 19.17 t, 4 loads; excavation 30 × 0.35 = 10.5 m³
geotextile 30 × 1.10 = 33 m² → 1 roll of 2 × 50 m; edging 2 × 10 = 20 m → 20 pieces
FAQ
Why order more than the compacted volume? Crushed stone and gravel are delivered loose and lose volume when compacted. The loose-to-compacted factor converts the finished (compacted) volume to the volume to order. The default 120% matches a UK supplier's figures for Type 1 sub-base (about 1.51 t/m³ loose, 1.81 t/m³ compacted); ask your supplier for your material.
How thick should the layers be? That depends on the subgrade, drainage, frost and the vehicles using it. The defaults are an example for a light-traffic domestic driveway, not a design. Heavy vehicles or poor ground need a designed pavement.
Why is each layer delivered separately? Different materials cannot share one truck. Each layer's loads are the larger of what fills the truck by volume and by weight; the total is the sum of the layers.
Which standard does this follow? None is cited. The take-off is geometry plus a density conversion; aggregate product standards classify the stone but give no quantity formula, and layer design is not performed here.
Assumptions and limits
- The listed parts are added as separate rectangles; they must not overlap, and the edging length is entered directly in list mode.
- Layers are flat and of constant thickness; crossfall, camber and side slopes are ignored.
- The geotextile is laid flat under the full area with an overlap allowance; turning it up the sides is not included.
- Bulk densities default to the same values as the bulk material calculator (crushed stone 1500, gravel 1650, sand 1600 kg/m³), consistent with published figures (Engineering ToolBox; Ibran Type 1 data). They and the 120% factor are estimates — use supplier data.
- No waste allowance beyond the compaction factor; excavation is area × total depth (no slopes, no bulking).