Getting a useful estimate
Calculate each material separately. Enter the loose depth or a supplier-approved allowance for a compacted layer.
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.
Work out each aggregate separately
Aggregate covers several products, including gravel and crushed stone. A total volume does not choose the right product for a surface or structural layer. For a patio or driveway, calculate each layer separately and use its specified material.
Enter length and width in metres and depth in millimetres. The result is cubic metres before any weight conversion. One tonne is 1,000 kg; converting cubic metres to tonnes needs the loose bulk density for the product you will buy.
A bulk bag is a pack size, not a tonne
Check the quoted net contents. Wickes lists its Type 1 jumbo bag at 800 kg, while Gravelmaster offers its named gravel product in approximately 850 kg and 1,000 kg bulk bags. Enter the size of the bag in your quote.
For a weight-labelled bag, also enter supplier density. The tool rounds up to whole bags and shows the surplus. You can compare small bags or bulk bags with a loose delivery by changing the bag size and price.
Compare what you will actually pay
Use prices including VAT for both options. Add delivery once, and include any minimum loose order or order increment. If delivery is included in the quoted price, enter zero for delivery. Bag delivery has its own field.
Confirm unloading and vehicle access before ordering. A cheaper material quote may cost more once delivery and the minimum load are included. The estimate does not add VAT or arrange delivery.
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 - Paving installation and delivery FAQsMarshalls
Different bedding systems for paving flags, joints, VAT and delivery access. No generic installation specification imported.
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.