Gravel Quantity Calculator

A gravel quantity calculator finds the volume of gravel needed to fill a rectangular area. A person enters length, width, and depth, and the calculator returns the result in cubic yards or cubic meters.

Gravel suppliers sell material by volume, not by area. A tape measure gives length and width in feet or meters, but a supplier needs a total volume. Converting between the two by hand is where most ordering mistakes happen, either too little material for the job or a large, costly surplus.

How to calculate gravel quantity

The basic formula for a rectangular area is:

Volume = Length × Width × Depth

This treats the gravel layer as a rectangular box. Multiplying the three dimensions gives the number of cubic units of space the gravel will fill.

Imperial formula (cubic yards)

Suppliers in the United States price gravel by the cubic yard, but a project is usually measured in feet. The formula converts feet to yards:

Cubic Yards = (Length in feet × Width in feet × Depth in feet) ÷ 27

The value 27 comes from the definition of a cubic yard: 3 ft × 3 ft × 3 ft = 27 cubic feet. Multiplying the three measurements in feet gives a volume in cubic feet, which is then divided by 27 to convert it to cubic yards.

Metric formula (cubic meters)

Where gravel is sold by the cubic meter, no conversion is needed if all three measurements are already in meters:

Cubic Meters = Length (m) × Width (m) × Depth (m)

Converting depth from inches or centimeters

Depth is often specified in inches or centimeters, so it must be converted to match the other two measurements before multiplying. To convert inches to feet, divide by 12. For example, a 4-inch depth equals 4 ÷ 12 = 0.33 feet. To convert centimeters to meters, divide by 100.

Example calculations

Driveway, imperial units. A driveway measures 24 feet long and 12 feet wide, with a gravel depth of 4 inches (0.33 feet).

Volume = 24 × 12 × 0.33 = 95.04 cubic feet Cubic yards = 95.04 ÷ 27 = 3.52 cubic yards

Garden path, metric units. A path measures 10 meters long and 1.2 meters wide, with a gravel depth of 5 centimeters (0.05 meters).

Cubic meters = 10 × 1.2 × 0.05 = 0.6 cubic meters

Choosing a gravel depth

The depth needed depends on how the surface will be used. Areas that carry vehicles need a deeper layer than walkways, and walkways need more than purely decorative beds. Drainage work, such as the gravel around the pipe in a French drain, depends on the size of the pipe and trench. The project plans, a local building authority or the gravel supplier can give a depth for the specific job.

Ordering extra material

A calculator gives the exact volume for the entered dimensions, but the volume delivered rarely equals the volume that ends up in place. Loose gravel contains air gaps between the stones that close up once the material is spread, driven over, or rained on, a process called compaction. Some material is also lost during delivery and spreading. To account for this, many people order somewhat more than the calculated volume. Soft or clay-heavy soil can absorb even more material as gravel settles into it, so projects on unstable ground may need a larger buffer.

Converting cubic yards and cubic meters

A cubic yard and a cubic meter are different sizes, since a yard (0.9144 m) is shorter than a meter. One cubic yard equals about 0.765 cubic meters, and one cubic meter equals about 1.31 cubic yards.

Frequently asked questions

How much gravel do I need for a driveway? Measure the length and width of the driveway in feet, choose a depth based on expected traffic, convert the depth to feet, and multiply the three numbers together. Divide the result by 27 to get cubic yards, then add some extra for compaction and waste.

How do I convert cubic feet to cubic yards? Divide the number of cubic feet by 27, since one cubic yard equals 27 cubic feet (3 ft × 3 ft × 3 ft).

How much does a cubic yard of gravel weigh? Weight depends on the stone type, the size of the stones and how wet they are, so it varies from one product to another. The supplier can give the weight per cubic yard or cubic meter for the specific material being ordered.

How much extra gravel should I order? A small margin above the calculated volume covers normal compaction and installation waste. Projects on soft, wet, or sloped ground often need a larger allowance. The supplier can advise on how much a given material settles.

Can this calculator handle irregular or non-rectangular areas? Yes, indirectly. Split the area into two or more rectangular sections, calculate the volume of each section separately, then add the results together. Curved areas, such as a circular patio, use a different formula based on the radius.

What depth of gravel should I use? It depends on the project. Areas that carry vehicles need the deepest layer, walkways less, and purely decorative areas the least. Going too shallow is the most common mistake, since gravel settles and disperses over time, leaving bare patches.

Background

Sand and gravel are among the most widely used building materials. The United States Geological Survey estimates that about 870 million metric tons of construction sand and gravel were produced in the United States in 2025. About 42 percent went into concrete, 20 percent into road base and road coverings, and 12 percent into construction fill.

References

1. National Institute of Standards and Technology. NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically. NIST SP 811 Appendix B.8 — 1 yard = 0.9144 meter; 1 cubic yard = 0.7645549 cubic meter.
2. U.S. Geological Survey. Mineral Commodity Summaries 2026: Sand and Gravel (Construction). USGS sand and gravel summary (PDF) — 870 million tons produced in 2025; 42 percent concrete aggregate, 20 percent road base and coverings, 12 percent construction fill.