Gravel & Mulch Calculator
Enter the area to cover, the depth, and your material's density to find the volume and weight needed.
Density varies by material: gravel is typically around 1,500-1,700 kg/m³, mulch around 250-400 kg/m³, and topsoil around 1,200-1,500 kg/m³ — check your specific product.
How gravel and mulch quantity is calculated
Volume is area × depth (with depth converted to meters), giving cubic meters directly, and cubic feet by multiplying by about 35.31 — useful since gravel and mulch are sometimes sold by volume.
Weight is volume × density. Since loose materials like gravel and mulch are often sold by weight (especially for delivery), multiplying the calculated volume by your material's density gives the total weight to order.
Frequently asked questions
What depth should I use for mulch?
A common recommendation is 5-10 cm (2-4 inches) for garden mulch, though this varies by mulch type and purpose — check guidance specific to your material and plants.
Why does gravel weigh so much more than mulch for the same volume?
Gravel is made of dense mineral rock, while mulch is typically lightweight organic material (bark, wood chips) with more air pockets — rock is simply much denser than wood.
Where do I find my material's exact density?
Check the supplier's product listing or datasheet — density varies meaningfully even within categories (like gravel size/type or mulch type), so a specific figure from your supplier gives a more accurate result than a general estimate.