Gravel CalculatorFree online other calculator — instant results, no sign-up
Gravel volume and weight.
About the Gravel Calculator
This calculator estimates the total volume and bulk weight of gravel needed to fill a rectangular area such as a driveway, pathway, or foundation bed. Landscapers, contractors, and homeowners use it to order raw aggregate in metric tonnes or cubic meters without over-purchasing.
- Length
- Length of the coverage area in meters (m), typically greater than 0.
- Width
- Width of the coverage area in meters (m), typically greater than 0.
- Depth
- Target layer thickness in centimeters (cm), typically between 2 cm and 30 cm depending on project use.
Formula and method
Volume (m³) = Length × Width × (Depth / 100) Weight (t) = Volume × 1.6
- LengthLength of the area in meters
- WidthWidth of the area in meters
- DepthDepth of the gravel bed in centimeters, converted to meters by dividing by 100
- 1.6Standard bulk density factor of approximately 1.6 metric tonnes per cubic meter (t/m³)
The tool converts depth from centimeters to meters by dividing by 100, then multiplies length, width, and converted depth to obtain volume in cubic meters. It then calculates weight by multiplying volume by a standard bulk density assumption of 1.6 metric tonnes per cubic meter, displaying both values rounded to two decimal places.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Length5 m
- Width3 m
- Depth8 cm
Results
- Volume1.2 m³
- Weight (≈1.6 t/m³)1.92 t
How to use the Gravel Calculator
- 1Measure the length and width of the site in meters.
- 2Choose the desired gravel depth in centimeters.
- 3Convert depth to meters and multiply length × width × depth to get volume in cubic meters (m³).
- 4Multiply volume by 1.6 to estimate the total weight in metric tonnes (t).
Reading your result
Volume (m³) tells you the physical space the gravel occupies, which is useful when ordering by truckload or bulk bag. Weight (t) represents the estimated mass in metric tonnes, which suppliers frequently use for pricing and load-limit dispatching.
Limitations
The calculation assumes a uniform rectangular excavation and does not factor in slope or irregular borders. It also applies a fixed bulk density of 1.6 t/m³, whereas actual gravel density varies between 1.4 and 1.8 t/m³ depending on rock type, grain size, moisture, and compaction.
Common questions
Why does the calculator assume 1.6 tonnes per cubic meter?+
A typical loose, mixed gravel containing crushed stone and sand averages roughly 1,600 kg/m³ (1.6 t/m³). Clean, single-size river stones may be closer to 1.5 t/m³, while crushed granite with fines can exceed 1.7 t/m³ when compacted.
How deep should a typical gravel path or driveway be?+
Walkways and decorative garden beds generally require a depth of 5 to 8 cm. Driveways usually require 10 to 20 cm, often split between a coarse sub-base layer and a finer surface gravel.
Should I order extra gravel beyond the calculated amount?+
Yes, ordering 5% to 10% extra is standard practice to account for soil settling, compaction under wheel or foot traffic, and minor measurement unevenness across the site.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.