Gravel Calculator
Planning a driveway, walkway, or patio? Use our free Gravel Calculator to estimate exactly how many tons, cubic yards, or bags of material you need. Whether you are using pea gravel, crushed stone, or sand, our tool helps you avoid over-ordering and calculates your estimated costs instantly.
Complete Guide to Gravel Calculation
Whether you are laying a new driveway, creating a drainage field, or designing a garden path, buying the correct amount of material is essential. Buying too little halts your project, while buying too much wastes money. This guide explains how to calculate gravel needs for any project.
1. The Gravel Formula
To find the amount of gravel needed, you must calculate the volume of the area to be filled. The basic formula is:
Volume = Length × Width × Depth
However, since gravel is sold by the Cubic Yard or Ton, and you likely measured your area in feet and inches, conversion is necessary:
- Step 1 (Area): Calculate square footage (Length × Width).
- Step 2 (Volume): Convert your depth to feet (Divide inches by 12). Multiply Area by Depth to get Cubic Feet.
- Step 3 (Cubic Yards): Divide Cubic Feet by 27 (since there are 27 cubic feet in a yard).
- Step 4 (Tons): Multiply Cubic Yards by the material density (typically 1.4 to 1.5 tons per yard for standard gravel).
2. How Deep Should My Gravel Be?
The depth of your gravel layer depends entirely on the application. A driveway carrying heavy vehicles needs a much thicker base than a decorative garden path.
| Project Type | Recommended Depth | Recommended Material |
|---|---|---|
| Walking Paths | 2 - 3 inches | Pea Gravel, Crushed Stone (1/4") |
| Standard Driveway | 4 - 6 inches | Crushed Stone #57, Driveway Gravel |
| Heavy Vehicle Driveway | 6 - 8 inches | Coarse Aggregate Base + Top Layer |
| Landscaping / Mulch | 2 - 3 inches | River Rock, Decorative Chips |
| Drainage / French Drain | 8 - 12 inches | Washed Clean Stone (No dust) |
3. Common Gravel Types & Densities
Not all stones weigh the same. Understanding the type of rock you are buying will help you estimate the tonnage more accurately.
- Pea Gravel: Small, rounded stones. Density approx. 100-110 lbs/ft³. Great for playgrounds and patios.
- Crushed Stone (#57): Angular, jagged edges that lock together. Density approx. 105 lbs/ft³ (approx 1.4 tons/yd). The standard for driveways.
- Sand: Much denser when wet. Dry sand is approx. 100 lbs/ft³, but wet sand can exceed 120 lbs/ft³.
- River Rock: Larger, smooth stones. Due to the air gaps between large stones, you may need slightly less tonnage per cubic yard compared to fine gravel.
4. Frequently Asked Questions (FAQ)
How much does a yard of gravel cover?
One cubic yard of gravel covers approximately 324 square feet at a depth of 1 inch. If you pour it 3 inches deep (common for walkways), one yard covers about 108 square feet.
How many tons are in a cubic yard of gravel?
On average, a cubic yard of standard gravel weighs about 2,800 lbs, which is 1.4 tons. However, this can vary between 1.2 and 1.7 tons depending on the stone type and moisture content.
What is the best gravel for a driveway?
#57 Crushed Stone is the most popular choice. It contains stones about 3/4" in size with jagged edges that lock together, preventing the gravel from sliding away under tires.