Gravel Calculator

The gravel calculator is a practical construction and landscaping tool that estimates how much gravel you need based on the dimensions of the area you want to fill. It calculates volume in cubic meters, weight in tonnes, and even total cost — all from three simple inputs. Select your gravel type, enter your measurements, and the calculator does the rest.

What Is Gravel?

Gravel is a loose aggregation of small rock fragments typically ranging from 2 mm to 64 mm in diameter. Naturally formed through weathering and erosion — or produced by mechanically crushing rock — it is a key material in construction, road surfaces, and landscaping. Its excellent drainage, durability, and surface-stabilizing properties make it one of the most widely used materials in civil and outdoor projects.

Common Gravel Types

• Pea Gravel — small, smooth, rounded stones commonly used for walkways and decorative landscaping.

• Crushed Stone — mechanically crushed rock (limestone or granite) with angular edges, ideal for high-strength construction and road base applications.

• Bank Run / River Gravel — a natural mix of sand, clay, and rock taken from riverbeds or banks, often used for fill and drainage.

The Gravel Volume Formula

The calculator uses this straightforward formula:

Length × Width × Depth = Volume

Use consistent units throughout. The calculator handles unit conversion automatically based on your selections. Once volume is known, the calculator multiplies it by the density of the selected gravel type to return the weight needed in tonnes.

How the Gravel Calculator Works

Inputs

• Gravel type — dropdown to select your gravel. Default: Gravel (dry, 1/4 - 2")

• Length — the longer dimension of your area (default unit: meters)

• Width — the shorter dimension of your area (default unit: meters)

• Depth — how deep the gravel layer needs to be (default unit: centimeters)

Outputs

• Area — calculated automatically from Length × Width (m²)

• Volume needed — total gravel volume required (m³)

• Weight needed — total weight based on volume and gravel density (tonnes)

Gravel Cost Section

• Price per unit of mass — enter your local gravel price per tonne (INR/t)

• Price per unit of volume — enter price per cubic meter if buying by volume (INR/m³)

• Total cost — estimated total spend returned in INR

How to Calculate Gravel — Step by Step

Example 1: Garden Path

You want to fill a garden path that is 6 m long, 1 m wide, and 5 cm deep.

Step 1: Convert depth to meters — 5 cm = 0.05 m. Step 2: Calculate volume — 6 × 1 × 0.05 = 0.3 m³. Step 3: The calculator applies the density of the selected gravel type and returns the weight in tonnes.

Enter: Length = 6, Width = 1, Depth = 5 cm, Gravel type = Gravel (dry, 1/4 - 2"). The calculator returns Area = 6 m², Volume = 0.3 m³, and the corresponding weight.

Example 2: Driveway Base

You need a gravel base for a driveway that is 10 m long, 3 m wide, and 10 cm deep.

Step 1: Convert depth — 10 cm = 0.10 m. Step 2: Calculate volume — 10 × 3 × 0.10 = 3 m³. Step 3: Enter your price per tonne in the cost section to get the total estimated spend.

Enter: Length = 10, Width = 3, Depth = 10 cm. Result: Area = 30 m², Volume = 3 m³, weight and cost calculated based on gravel type and price entered.

Gravel Project Reference Table

Note: Depths are general industry guidelines. Adjust based on your specific project and local recommendations.

Frequently Asked Questions

How much gravel for a 10x10 area?

For a 10 ft × 10 ft (approximately 3 m × 3 m) area at a 5 cm depth, you need roughly 0.45 m³ of gravel. At 10 cm depth, that doubles to about 0.9 m³. Enter your exact dimensions into the gravel calculator to get the precise volume and weight.

What area will 20 kg of gravel cover?

Coverage depends on depth and gravel density. At a 5 cm depth, 20 kg of standard dry gravel covers roughly 0.25 m². Shallower depths give more coverage; deeper fills cover less area. Use the calculator by working backwards — enter a small area and depth until the weight output matches your available quantity.

What is the default gravel type in this calculator?

The default gravel type is Gravel (dry, 1/4 - 2") — a common dry gravel size ranging from approximately 6 mm to 50 mm. You can change this using the Gravel type dropdown to match the material you're ordering.

Can I calculate gravel cost with this tool?

Yes. The "How much will the gravel cost me?" section lets you enter a price per tonne or per cubic meter. The calculator multiplies your required weight or volume by the unit price and returns the total estimated cost in INR.