Use this Gravel Calculator to estimate how much gravel you need for a driveway, walkway, patio, garden path, drainage area, or landscaping project.
Enter the length, width, and depth of your project to calculate the estimated gravel volume in cubic feet and cubic yards. You can also use the calculation to estimate how much material to order.
Gravel Calculator
The basic formula is:
Length × Width × Depth = Volume
When measurements are in feet:
Cubic Yards = Length × Width × Depth ÷ 27
For example, if an area is 20 feet long, 10 feet wide, and 4 inches deep:
- Convert 4 inches to feet:
4 ÷ 12 = 0.333 feet - Calculate cubic feet:
20 × 10 × 0.333 = 66.67 cubic feet - Convert to cubic yards:
66.67 ÷ 27 = 2.47 cubic yards
You need approximately 2.47 cubic yards of gravel before accounting for compaction, settling, or additional material.
How Much Gravel Do I Need?
The amount of gravel required depends primarily on:
- Length of the area
- Width of the area
- Desired depth
- Shape of the area
- Type of gravel
- Compaction requirements
For a rectangular area, use:
Cubic Yards = Length × Width × Depth ÷ 27
Always convert inches to feet before using the formula.
Common Gravel Depths
Typical project depths vary depending on the application.
| Application | Common Planning Range |
|---|---|
| Decorative gravel | 2–3 inches |
| Garden paths | 2–4 inches |
| Walkways | 3–4 inches |
| Driveway surface | 4–6+ inches |
| Gravel base | Project-specific |
These are general planning ranges, not universal construction requirements. The correct depth depends on the material, soil, drainage, traffic, climate, and project design.
Gravel Calculator Formula
For a rectangular area:
Cubic Feet = Length × Width × Depth
Then:
Cubic Yards = Cubic Feet ÷ 27
Or directly:
Cubic Yards = Length × Width × Depth ÷ 27
If depth is measured in inches:
Depth in Feet = Depth in Inches ÷ 12
Example
A 30 × 12-foot area needs 5 inches of gravel.
Convert the depth:
5 ÷ 12 = 0.4167 feet
Calculate volume:
30 × 12 × 0.4167 = 150 cubic feet
Convert to cubic yards:
150 ÷ 27 = 5.56 cubic yards
The theoretical requirement is approximately 5.56 cubic yards.
Gravel Calculator for a Driveway
Gravel driveways often require more material than decorative landscaping because they may need several layers.
For example, suppose a driveway is:
- 50 feet long
- 12 feet wide
- 6 inches deep
Convert 6 inches:
6 ÷ 12 = 0.5 feet
Calculate:
50 × 12 × 0.5 = 300 cubic feet
Convert:
300 ÷ 27 = 11.11 cubic yards
The estimated volume is approximately 11.1 cubic yards.
If the driveway uses multiple layers with different materials or thicknesses, calculate each layer separately.
Gravel Driveway Layers
A gravel driveway may include:
- Prepared subgrade
- Base material
- Intermediate gravel layer
- Surface gravel
The appropriate structure depends on soil conditions, drainage, expected traffic, local climate, and project specifications.
Gravel Calculator for a Walkway
For a rectangular walkway, measure:
- Length
- Width
- Desired gravel depth
For example:
40 ft × 4 ft × 3 inches
Convert the depth:
3 ÷ 12 = 0.25 ft
Then:
40 × 4 × 0.25 = 40 cubic feet
Convert to cubic yards:
40 ÷ 27 = 1.48 cubic yards
You would need approximately 1.5 cubic yards of gravel before considering settling or other project-specific factors.
Gravel Calculator for Landscaping
Decorative gravel is commonly used for:
- Garden beds
- Pathways
- Borders
- Drainage areas
- Around trees
- Rock gardens
- Decorative ground cover
For a rectangular landscaping area:
Length × Width × Depth ÷ 27 = Cubic Yards
For example, a 25 × 15-foot garden area covered with 3 inches of gravel requires:
25 × 15 × 0.25 = 93.75 cubic feet
Then:
93.75 ÷ 27 = 3.47 cubic yards
The estimate is approximately 3.5 cubic yards.
Gravel Calculator for a Patio
If gravel is being used as a base beneath pavers or another surface, calculate the base separately from any decorative surface gravel.
For example:
- Length: 20 ft
- Width: 15 ft
- Depth: 4 in
4 ÷ 12 = 0.333 ft
20 × 15 × 0.333 = 100 cubic feet
100 ÷ 27 = 3.70 cubic yards
The estimated volume is approximately 3.7 cubic yards.
The appropriate base thickness depends on the paving system, soil conditions, drainage, expected loads, and installation specifications.
Gravel Calculator for Drainage
Gravel is often used around drainage systems, French drains, and other water-management applications.
The amount required depends on the dimensions of the trench or drainage area.
For a rectangular trench:
Length × Width × Depth ÷ 27
For example:
- Length: 30 ft
- Width: 1 ft
- Depth: 2 ft
30 × 1 × 2 = 60 cubic feet
60 ÷ 27 = 2.22 cubic yards
This produces a theoretical volume of approximately 2.22 cubic yards.
For drainage systems, the final design should account for the pipe, void spaces, fabric, surrounding soil, and drainage requirements.
Gravel Calculator for a Circular Area
For a circular area, use the cylinder formula:
Volume = π × Radius² × Depth
If the measurements are in feet, divide the resulting cubic feet by 27 to obtain cubic yards.
Example
A circular area has:
- Diameter: 20 ft
- Depth: 3 in
First calculate the radius:
20 ÷ 2 = 10 ft
Convert depth:
3 ÷ 12 = 0.25 ft
Calculate:
π × 10² × 0.25 ≈ 78.54 cubic feet
Convert to cubic yards:
78.54 ÷ 27 ≈ 2.91 cubic yards
So approximately 2.9 cubic yards are required before accounting for additional material.
Gravel Calculator for Irregular Areas
Many landscaping and driveway projects aren’t perfect rectangles.
For an irregular area, divide the project into smaller shapes.
For example:
Section A + Section B + Section C = Total Volume
Calculate the cubic yards for each section separately, then add the results.
For triangular sections:
Area = Base × Height ÷ 2
Then multiply the area by the depth to determine volume.
For complicated shapes, creating a simple sketch and dividing the area into rectangles, triangles, or circles can make the calculation much easier.
How Many Tons of Gravel Do I Need?
A cubic yard measures volume, while a ton measures weight.
The conversion between cubic yards and tons is not fixed because gravel density varies.
Factors affecting weight include:
- Gravel type
- Rock size
- Moisture
- Density
- Compaction
- Material composition
A supplier may provide an approximate conversion such as tons per cubic yard for a specific gravel product.
The safest approach is:
Cubic Yards × Supplier’s Tons per Cubic Yard = Estimated Tons
Always use the supplier’s stated density when ordering by weight.
How Much Does a Cubic Yard of Gravel Weigh?
There is no single universal weight for a cubic yard of gravel.
Different gravel products have different densities, and moisture can also change the weight.
For estimating transportation or ordering by weight, ask the supplier for the weight per cubic yard of the specific gravel product.
This is more reliable than using a generic conversion.
How Many Tons Are in a Cubic Yard of Gravel?
The answer depends on the type and density of the gravel.
Some gravel products may weigh around 1.3 to 1.8 tons per cubic yard, but this is only a broad planning range and should not be treated as a universal conversion.
For an accurate order:
- Calculate the required cubic yards.
- Find the supplier’s stated density.
- Multiply the volume by the stated weight per cubic yard.
Gravel Coverage Calculator
One cubic yard contains 27 cubic feet.
The area covered by one cubic yard depends on the depth.
Approximate theoretical coverage:
| Depth | Coverage per Cubic Yard |
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
| 5 inches | 64.8 sq ft |
| 6 inches | 54 sq ft |
| 8 inches | 40.5 sq ft |
| 12 inches | 27 sq ft |
These figures represent mathematical volume and do not account for compaction, settling, uneven surfaces, or waste.
How Much Area Does 1 Ton of Gravel Cover?
Coverage by ton depends on the density of the specific gravel.
If a supplier tells you that one ton equals a particular volume, you can calculate coverage from that volume.
For example:
Coverage = Volume ÷ Depth
Because gravel density varies, avoid assuming that every ton covers exactly the same area.
How Deep Should Gravel Be?
The appropriate gravel depth depends on the application.
Decorative landscaping gravel may require a relatively shallow layer, while a driveway or structural base may require multiple layers with greater total thickness.
Factors to consider include:
- Intended use
- Vehicle traffic
- Soil conditions
- Drainage
- Gravel size
- Compaction
- Climate
- Existing base
- Local construction requirements
For driveways and load-bearing applications, the correct depth and base construction should be determined based on the actual site conditions and project requirements.
Should You Add Extra Gravel?
The calculator gives you a theoretical volume.
Real projects may require additional material because of:
- Uneven ground
- Measurement differences
- Compaction
- Settling
- Spillage
- Irregular shapes
- Material displacement
A small additional allowance may be appropriate, but the amount depends on the material and project.
For a driveway, for example, compaction should be considered when determining the amount to order.
Gravel Size Matters
Gravel is available in many sizes and types.
Common categories include:
- Crushed stone
- Pea gravel
- River rock
- Drainage gravel
- Decorative gravel
- Road base
- Crusher run
Different sizes behave differently under traffic, drainage, and compaction.
For example, smaller rounded stones may behave differently from angular crushed stone. The best material depends on the application.
Common Gravel Calculation Mistakes
Forgetting to Convert Inches
If your depth is 4 inches, don’t enter 4 as though it were 4 feet.
Convert:
4 ÷ 12 = 0.333 feet
Forgetting to Divide by 27
Multiplying dimensions in feet gives cubic feet.
To convert to cubic yards:
Cubic Feet ÷ 27
Confusing Tons With Cubic Yards
Tons measure weight. Cubic yards measure volume.
Ignoring Multiple Layers
A driveway may contain several different material layers. Calculate each layer separately.
Not Accounting for Compaction
Some gravel applications become more compact after installation. Follow project or supplier recommendations.
Measuring an Irregular Area as a Rectangle
If the actual area is irregular, divide it into smaller sections rather than using a rough rectangle that significantly overestimates or underestimates the area.
Gravel Calculator Example
Let’s calculate gravel for a 60-foot-long driveway that is 12 feet wide and requires 5 inches of gravel.
Step 1: Convert the Depth
5 ÷ 12 = 0.4167 feet
Step 2: Calculate Cubic Feet
60 × 12 × 0.4167 = 300 cubic feet
Step 3: Convert to Cubic Yards
300 ÷ 27 = 11.11 cubic yards
The theoretical volume is approximately:
11.1 cubic yards
The actual quantity to order may be higher depending on compaction, site conditions, and the supplier’s recommendations.
Frequently Asked Questions
What is a gravel calculator?
A gravel calculator estimates the volume of gravel needed based on the length, width, and depth of an area.
How do I calculate how much gravel I need?
Multiply the length by the width and depth, using the same unit for all measurements. If calculating cubic yards from feet, divide the result by 27.
How many cubic yards of gravel do I need?
Use:
Length × Width × Depth ÷ 27
when the dimensions are measured in feet.
How much gravel do I need for a 10 × 20 area?
The answer depends on the depth. At 4 inches deep:
10 × 20 × 0.333 ÷ 27 ≈ 2.47 cubic yards
How many cubic feet are in a cubic yard of gravel?
One cubic yard contains 27 cubic feet.
How many tons are in a cubic yard of gravel?
It depends on the gravel’s density. Ask your supplier for the specific material’s weight per cubic yard.
How deep should a gravel driveway be?
There is no universal depth for every driveway. Required depth depends on soil, drainage, traffic, gravel type, base construction, climate, and local conditions.
How much does one cubic yard of gravel cover?
At 3 inches deep, one cubic yard theoretically covers approximately 108 square feet.
Can I use this calculator for pea gravel?
Yes. The volume calculation works for pea gravel and other bulk gravel products. Weight conversions should use the density provided for the specific product.
Should I add extra gravel?
You may need additional material to account for compaction, settling, uneven surfaces, and measurement variations. The appropriate allowance depends on the project.
Can I calculate gravel for a circular area?
Yes. Use:
π × Radius² × Depth
Then convert the resulting cubic feet to cubic yards by dividing by 27.
Final Thoughts
The Gravel Calculator provides a quick way to estimate the amount of gravel needed for driveways, walkways, patios, landscaping, drainage projects, and other applications.
For a rectangular project, remember the basic formula:
Cubic Yards = Length × Width × Depth ÷ 27
Measure carefully, convert inches to feet when necessary, and consider compaction, settling, and site conditions before placing your final order.
For major construction, drainage, structural, or load-bearing projects, use the calculator as an estimate and verify the required material quantity with the project specifications or a qualified professional.