Gravel Calculator
Estimate how much gravel you need for driveways, paths, patios, and drainage projects.
How this gravel calculator helps
Ordering gravel is one of those tasks that seems simple at first, but can get expensive if you guess wrong. Too little material means delays and a second delivery charge. Too much means leftover piles and wasted money. This calculator gives you a practical estimate based on volume, density, and a built-in waste factor.
What the calculator measures
The tool starts with three project dimensions:
- Length of the area
- Width of the area
- Depth of gravel needed
It then converts those dimensions into volume and uses your selected density to estimate total weight. Finally, it applies a waste/compaction percentage so your order is more realistic for field conditions.
Outputs you get
- Required gravel volume in cubic feet, cubic yards, and cubic meters
- Estimated total weight in pounds, short tons, and kilograms
- Approximate number of 40 lb and 50 lb bags
- Estimated material cost if you enter a price per ton
Gravel depth guidelines by project type
Depth can vary based on soil quality, traffic load, and base preparation, but these rough ranges are commonly used:
- Walkways and garden paths: 2–3 inches
- Decorative landscaping: 1.5–2.5 inches
- Patio base layers: 4–6 inches
- Light-duty driveways: 4–6 inches minimum
- Heavy vehicle driveways: 6+ inches with proper sub-base
- French drains: depth varies by design and pipe diameter
Choosing the right gravel
Different projects call for different aggregate types. A few common options:
- Crushed stone: angular, compacts well, great for bases
- Pea gravel: smooth and decorative, less stable for load-bearing areas
- River rock: decorative drainage applications
- Crusher run: blend of stone and fines, excellent for driveways
Tip on density
Density varies by stone type, moisture, and gradation. If your supplier gives a specific tons-per-cubic-yard value, use that to refine your estimate before ordering.
Example estimate
Suppose you are building a gravel pad that is 20 ft long, 12 ft wide, and 4 inches deep.
- Convert depth: 4 in = 0.333 ft
- Volume: 20 × 12 × 0.333 ≈ 80 ft³
- In cubic yards: 80 ÷ 27 ≈ 2.96 yd³
- With 10% waste: 2.96 × 1.10 ≈ 3.26 yd³
So you would typically order around 3.25 to 3.5 cubic yards, depending on supplier increments and site conditions.
Ordering and installation tips
- Always round up slightly when ordering bulk material.
- Confirm whether the supplier sells by volume (cubic yard) or weight (ton).
- Ask about delivery minimums and spread fees.
- Use landscape fabric only when appropriate to the design.
- Compact in lifts for thicker sections, especially for driveways.
Final note
This calculator provides a strong planning estimate, not a structural engineering design. For retaining walls, heavy equipment surfaces, or drainage-critical installations, consult a qualified local contractor or engineer. Still, for most residential gravel projects, this tool will get you very close and help you budget with confidence.