Free Gravel Calculator Online
Whether you’re filling a driveway, leveling a base layer, or building a patio foundation, using a gravel calculator ensures you order the right amount of material. Estimating gravel by guesswork leads to wasted money or extra trips to the store. This tool uses basic dimensions to determine how many cubic yards, tons, or bags you’ll need based on your project size.
Gravel Calculator
What Is a Gravel Calculator?
A gravel calculator helps determine how much gravel is needed to fill a defined area. By entering the length, width, and depth of your project, you get results in cubic yards, cubic feet, or tons depending on your selected gravel type. This method works well for driveways, garden paths, walkways, patios, and drainage trenches.
Gravel Volume Formula
$$Volume (cubic feet)=Length (ft)×Width (ft)×Depth (ft)\text{Volume (cubic feet)} = \text{Length (ft)} \times \text{Width (ft)} \times \text{Depth (ft)}Volume (cubic feet)=Length (ft)×Width (ft)×Depth (ft)$$
Convert to cubic yards: $$Cubic Yards=Volume in cubic feet27\text{Cubic Yards} = \frac{\text{Volume in cubic feet}}{27}Cubic Yards=27Volume in cubic feet$$
To convert cubic yards to tons, multiply by the gravel density (typically 1.4 to 1.7 tons per cubic yard depending on type).
Example Calculation
$$Area: 20 ft × 10 ft, depth of 4 inches$$
$$Convert Depth: 4 in ÷ 12 = 0.33 ft$$
$$Volume: 20 × 10 × 0.33 = 66 cubic feet$$
$$Cubic Yards: 66 ÷ 27 ≈ 2.44 cubic yards$$
$$Tons (using 1.5 density): 2.44 × 1.5 = 3.66 tons$$
Order about 3.75 tons to cover waste and compaction.
Gravel Types and Uses
- Crushed Stone: Great for driveways and foundations
- Pea Gravel: Best for landscaping and walkways
- River Rock: Ideal for decorative features
- Base Gravel: Perfect for under concrete slabs
- Drainage Gravel: For French drains and wet areas
Each has its own weight and size, which affects your gravel volume calculation.
Tips to Use the Gravel Calculator Correctly
- Always double-check your area dimensions
- Convert inches to feet before calculating
- Round up for safety gravel compacts during installation
- Know your gravel’s density (tons per cubic yard)
- Choose your gravel type before estimating
Common Mistakes to Avoid
- Not accounting for compaction
- Ignoring gravel shape and voids
- Forgetting depth uniformity
- Using the wrong unit (cubic feet vs. cubic yards)
FAQs
What’s the average gravel depth for a driveway?
Typically 4″–6″ of compacted base material, sometimes topped with finer gravel.
Can I calculate gravel for circular areas?
Yes. Use the formula: $$Volume=π×r2×Depth\text{Volume} = \pi \times r^2 \times \text{Depth}Volume=π×r2×Depth$$
Then convert the result to cubic yards or tons.
How much does a yard of gravel weigh?
Around 2,800 to 3,400 pounds, depending on gravel type and moisture content.
How many bags of gravel are in a cubic yard?
One cubic yard = about 54 50-pound bags.
Final Note
Using a gravel calculator saves time, money, and headaches. Get the correct volume, avoid material shortages, and prevent over-ordering. Whether you’re filling a trench, building a path, or leveling an outdoor surface, this calculator is your best tool to keep the project on budget and on track.