Crushed Stone Calculator
Calculate the volume, weight, and number of truckloads of crushed stone by area or direct volume input.
Surface area to be covered, in square meters
Depth of the stone layer in centimeters
The grade determines bulk density
Calculation formula
Weight = Volume × Bulk density
Volume (m³) = area (m²) × thickness (m). Weight (t) = volume × bulk density for the selected grade. Number of truckloads = weight ÷ 10 t.
About the crushed stone calculator
This calculator helps you estimate how much crushed stone or gravel you need for a driveway, patio, foundation base, drainage layer, or garden path. Enter the area and desired layer thickness, and the tool instantly shows the required volume in cubic meters, total weight in tonnes, and number of truck deliveries.
Bulk density varies by grade: 5–20 mm stone is approximately 1.37 t/m³, 20–40 mm is 1.35 t/m³, 40–70 mm is 1.32 t/m³, and 5–20 mm gravel is 1.40 t/m³. These values are used to convert volume to weight accurately.
It is recommended to add a 5–10% buffer to the calculated volume to account for compaction and settling after the material is placed and compacted.
Why use this calculator
Accurate m³ to tonnes conversion
The calculator applies grade-specific bulk density so the weight figure accurately reflects the material you are ordering.
Truckload count
Delivery quantities are expressed in 10-tonne truck loads, making it straightforward to request the right number of deliveries.
Two input modes
Enter area plus depth, or supply a known volume directly — whichever suits your project data.
Frequently asked questions
How do I convert cubic meters of crushed stone to tonnes?
Multiply the volume in m³ by the bulk density of the grade: 5–20 mm × 1.37, 20–40 mm × 1.35, 40–70 mm × 1.32. The calculator does this automatically once you select the grade.
How many tonnes of crushed stone are in one cubic meter?
It depends on the grade: 1 m³ of 5–20 mm stone weighs about 1.37 t, 20–40 mm about 1.35 t, 40–70 mm about 1.32 t, and 5–20 mm gravel about 1.40 t.
What is the bulk density of crushed stone?
Bulk density by grade: 5–20 mm ≈ 1.37 t/m³, 20–40 mm ≈ 1.35 t/m³, 40–70 mm ≈ 1.32 t/m³, gravel 5–20 mm ≈ 1.40 t/m³. Larger particles leave more void space, reducing overall density.
How many truck loads do I need?
A standard 10-tonne dump truck carries one load. Divide the total weight in tonnes by 10 to get the number of deliveries. The calculator rounds up to the nearest whole truck.
Which grade of crushed stone should I choose?
Use 5–20 mm for paving bases and foundation sub-bases, 20–40 mm for road bases and large hardstandings, and 40–70 mm for drainage layers where maximum permeability is needed.
Should I order extra stone as a buffer?
Yes — add 5–10% to the calculated volume. Crushed stone compacts under load and vibration, so the finished layer is typically slightly thinner than the loose-tipped depth.