Measure your project
Measure the driveway footprint. Use your contractor’s specified depths for each layer. Add any turning or parking areas as separate sections.
Measure the space you need to fill. Rectangles use length and width; circles use diameter. For several sections, choose combined areas and add rectangles, then subtract exclusions. The final area must be greater than zero.
Include parking and turning areas
A driveway footprint can contain the entrance strip, a parking bay and a turning area. Give each rectangle a name. Keep adjacent sections separate and avoid counting an overlap twice. Subtract planted islands or other areas outside the material order.
If the surface thickness changes, put that gravel depth on the affected section. Type 1 has a separate depth for the same rectangle. A thicker base does not increase the gravel layer unless you change its surface depth too.
Separate the surface order from the compacted base
The surface result is the gravel volume at the depth you enter. The base result starts from the specified compacted thickness and increases it by your stated loose-order allowance. Enter the product density separately for gravel and Type 1; neither layer borrows the other’s density.
For a hypothetical 5 m by 2 m driveway, a 40 mm gravel layer is 0.4 m³. A 100 mm base is 1 m³ before allowance; a supplier-confirmed 20% ordering allowance would make it 1.2 m³. These numbers demonstrate the arithmetic, not a driveway specification.
Compare the loads you can receive
Quote surface gravel and Type 1 as separate products. A loose-load minimum can make the delivered order larger than the measured requirement. Compare that order with whole small bags and bulk bags, including the separate transport charges.
If one supplier charges once to deliver both products, allocate that charge to one line or split it between them. Do not enter the full charge on both lines. Confirm where the vehicle can unload, where the material will be stored and whether the quote covers your postcode.
Volume formula
Allowance applies once to each volume layer. No density or compaction factor is assumed. If buying by weight, enter the density for your supplier’s product in the units shown.
Sources & what they cover
- NIST SI conversion factorsNational Institute of Standards and Technology
Exact US customary and SI conversion factors; no material or installation recommendations.
Source checked - MOT Type 1 jumbo bagWickes
Named sub-base product and 800 kg bag. Bag weight can vary with moisture. No universal density or construction depth imported.
Source checked - River Washed Gravel 10mmGravelmaster
Product-specific 20 kg bags and approximately 850 kg or 1,000 kg bulk bags, plus loose delivery. These sizes are not universal.
Source checked
We check what each reference covers. A source check does not mean a specialist has reviewed this tool. You supply the depths, densities, prices and blend proportions.