Measure your project
Split bends into short rectangles and add their areas. Subtract planted islands and enter the specified depth for each material.
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.
Measure bends in short sections
For a straight path, choose one rectangle. For bends or changing widths, use named sections such as Gate run, Side passage and Back border. Measure each length and width; shorter rectangles can approximate a curved outline. This does not trace a curve automatically.
The area total adds included rectangles and subtracts exclusions. An overlap entered twice will overstate the order. Split that overlap out or subtract it with the depth of the material being excluded.
Keep varying depths visible
The layer depth applies to sections where that material’s depth is blank. Enter a separate surface depth where the gravel thickness changes, and a separate base depth where your specification changes the Type 1 thickness.
For example, a 2 m by 2 m section at 50 mm plus a 3 m by 2 m section at 100 mm needs 0.8 m³ of gravel before allowance. If both sections instead used 50 mm, the order would be 0.5 m³. These are measurement examples, not recommended path depths.
Choose a practical bag order
Compare the small bags, bulk bags and loose load for each product. A narrow path may need less than a supplier’s minimum tipped load; whole-bag rounding can also leave spare material. The comparison shows that surplus alongside the quoted cost.
Bulk-bag contents vary. Use the net quantity on the actual quote and the loose product density when the contents are given by weight. Check how delivered material will reach the path and keep the access arrangement separate from the arithmetic.
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.