Gravel Calculator
Calculate how much gravel you need for a path, driveway, or drainage bed — in cubic yards, tons, and estimated cost.
Gravel Calculator: Formula, Worked Examples & Complete Guide
Written by Magesh | Financial Tools & Calculation Specialist · Last updated July 31, 2026
In two sentences: A gravel calculator converts the length, width, and depth of your project into cubic yards, then multiplies by a density factor of roughly 1.4 to 1.5 tons per cubic yard to tell you exactly how much to order from your supplier. This guide breaks down the full formula, worked examples for driveways and garden beds, and the coverage shortcuts contractors actually use on the job.
What Is a Gravel Calculator?
A gravel calculator estimates how much gravel, crushed stone, or similar aggregate material you need for a project, and converts between the two units suppliers typically use — cubic yards (a volume measurement) and tons (a weight measurement). Since quarries and gravel yards almost always sell by weight while project area is naturally measured by volume, this conversion step is unavoidable for nearly every driveway, path, or landscaping job.
The Gravel Calculator Formula
Step 1: Volume (cubic feet) = Length (ft) × Width (ft) × Depth (ft)
Step 2: Volume (cubic yards) = Volume (cubic feet) ÷ 27
Step 3: Weight (tons) = Volume (cubic yards) × Density (tons per cubic yard)
Gravel density typically ranges from 1.4 to 1.7 tons per cubic yard, with 1.4–1.5 commonly used as a general planning figure for standard clean gravel and pea gravel, while denser base materials with fines can run closer to 1.7.
The quick square-footage shortcut
For a fast estimate when you know your area in square feet and depth in inches:
Cubic Yards = (Square Feet × Depth in Inches) ÷ 324
Tons = Cubic Yards × 1.4 to 1.5
Worked Examples
Example 1: A standard driveway
A 12-foot by 100-foot driveway at 4 inches deep (0.333 feet):
Volume = 12 × 100 × 0.333 = 400 cubic feet
Cubic Yards = 400 ÷ 27 ≈ 14.8 cubic yards
Tons = 14.8 × 1.4 ≈ 20.7 tons
With 10% waste: 20.7 × 1.10 ≈ 23 tons — order 23 tons
Example 2: A small garden bed
A 10-foot by 6-foot garden bed with pea gravel at 2 inches deep (0.167 feet):
Volume = 10 × 6 × 0.167 = 10 cubic feet
Cubic Yards = 10 ÷ 27 ≈ 0.37 cubic yards
Tons = 0.37 × 1.4 ≈ 0.52 tons
Example 3: Using the square-footage shortcut
A 20-foot by 10-foot pea gravel patio at 2 inches thick:
Square Feet = 20 × 10 = 200 sq ft
Cubic Yards = (200 × 2) ÷ 324 ≈ 1.23 cubic yards
Tons = 1.23 × 1.4 ≈ 1.73 tons
Example 4: A circular gravel feature
A circular gravel patio with a 6-foot radius, 3 inches deep (0.25 feet):
Area = π × 6² ≈ 113.1 sq ft
Volume = 113.1 × 0.25 ≈ 28.3 cubic feet
Cubic Yards = 28.3 ÷ 27 ≈ 1.05 cubic yards
Tons = 1.05 × 1.4 ≈ 1.47 tons
Step-by-Step: How to Use a Gravel Calculator
- Measure the length and width of your project area in feet — for circular areas, use the radius and the area formula (π × radius²) instead.
- Determine your desired depth, converting from inches to feet by dividing by 12.
- Multiply length × width × depth to get cubic feet, then divide by 27 for cubic yards.
- Multiply cubic yards by your gravel’s density (1.4–1.7 tons per cubic yard) to get the weight in tons.
- Add 5–10% extra to account for settling, compaction, and uneven ground before finalizing your order.
Coverage Reference: How Far Gravel Actually Goes
Understanding how coverage changes with depth helps you sanity-check any gravel calculator result:
| Depth | Coverage per Cubic Yard | Coverage per Ton (approx.) |
|---|---|---|
| 1 inch | 324 sq ft | ~230 sq ft |
| 2 inches | 162 sq ft | ~115 sq ft |
| 3 inches | 108 sq ft | ~76 sq ft |
| 4 inches | 81 sq ft | ~58 sq ft |
Notice that doubling your depth doesn’t just double your material cost — it roughly doubles it exactly, since coverage is inversely proportional to depth for a fixed volume.
Choosing the Right Depth for Your Project
- Decorative paths and garden beds: 2–3 inches is typically sufficient for appearance and light foot traffic.
- Standard residential driveways: 4 inches of surface gravel is the common baseline for light vehicle use.
- Heavy-traffic driveways or base layers: 4 inches of compacted road base plus 2 inches of surface gravel, or up to 6 inches total for areas seeing heavier vehicles.
- Drainage trenches: depth depends on the specific drainage design, but typically ranges from 4 to 12 inches depending on the application.
Getting an Accurate Gravel Calculator Estimate Before You Order
A gravel calculator is only as reliable as the measurements and density figure you use, so a few extra minutes of preparation avoids an expensive reorder trip.
Tips for a more accurate gravel calculator result
- Confirm your supplier’s actual density figure, rather than relying solely on a generic 1.4–1.5 tons-per-yard average, since different gravel types and moisture content can shift this number meaningfully.
- Measure depth in the units your gravel calculator expects. Depth almost always arrives in inches while the core formula wants feet — forgetting to divide by 12 throws the whole order off by a factor of twelve.
- Account for compaction on driveway base layers. A gravel calculator estimates loose volume, but compacted base material settles, so many contractors add extra depth specifically for base layers that will be compacted.
- Round up to your hauler’s delivery increment. A truck arriving half a yard short of what a gravel calculator recommended often means a costly second trip, so rounding up to the nearest convenient delivery amount is usually worth the small extra cost.
Frequently Asked Questions
A cubic yard is a volume measurement (3 feet × 3 feet × 3 feet = 27 cubic feet), while a ton is a weight measurement. Gravel typically weighs 1.4 to 1.7 tons per cubic yard, so the two units aren’t interchangeable without applying that density conversion.
Different gravel types — clean pea gravel versus a dense-graded base material with fines — pack differently and hold different amounts of moisture, which changes their weight per cubic yard. Always ask your specific supplier for their material’s density rather than relying solely on a generic average.
Adding 5–10% extra covers settling, compaction, and minor measurement inaccuracies that are common even on carefully planned projects, ensuring you don’t run short mid-job.
Yes — the volume formula is identical (length × width × depth), but you’ll need to swap in the correct density for your specific material, since sand, topsoil, and gravel all weigh different amounts per cubic yard.
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In summary, a gravel calculator turns your project’s dimensions into an accurate order quantity in both cubic yards and tons, and understanding the density conversion step is what keeps you from ordering the wrong amount when your supplier prices by weight instead of volume.
About the author: Magesh is a Financial Tools & Calculation Specialist focused on building and fact-checking online calculators across construction, landscaping, and home improvement topics.
Note: This calculator and article are provided for general educational and informational purposes only. Gravel density varies by material and supplier. Always confirm exact density and pricing with your local supplier before finalizing an order.