Gravel Calculator

Ordering gravel usually means translating a length and width into a number a quarry or supplier will actually recognize: tons. Most suppliers sell and deliver gravel by weight, not by volume, so a gravel calculator that only gives you cubic yards is only telling you half of what you need.

This gravel calculator solves that by working in tons first, while still showing cubic yards, truckloads, and bags. It also handles a project most tools skip entirely: a driveway or path with a compacted base layer of one material and a decorative top layer of another. Add each layer as its own area, pick its own material, and the calculator totals everything, including separate overage and compaction allowances.

1. How the Gravel Calculator Works

Each area you add has its own shape, either rectangle or circle, its own material, and its own depth. The calculator converts depth from inches to feet, multiplies it by the footprint, and gets a raw volume in cubic feet for that area.

It then applies two separate adjustments: an overage percentage for spillage and small voids, applied to every area, and a compaction percentage that only applies to areas you mark as compacted. A driveway base can carry the compaction allowance while a decorative top layer right above it does not, since a top layer that is not driven on usually is not packed down the same way.

Each area's adjusted volume is converted to tons using that area's own material density, so a project with a crushed stone base and a pea gravel top layer gets an accurate weight for each, not one blended guess.

2. How to Use the Gravel Calculator

1. Choose a shape for your first area, Rectangle or Circle.
2. Enter the length and width in feet, or the diameter in feet for a circle.
3. Pick the material for that area, or enter a custom density if your supplier has given you one.
4. Enter the depth in inches for that area.
5. Add another area if your project has a second layer or a separate section, with its own material if needed.
6. Mark whether that area is compacted, and choose a project type to load a sensible starting compaction percentage.
7. Optionally enter a price per ton or per cubic yard to see an estimated cost.

3. Gravel Calculator Formula

Each area's volume then gets the overage and compaction allowances applied, one after the other, before converting to yards and tons:

4. Worked Example

Using the calculator's defaults: a two-layer driveway, 40 ft long and 12 ft wide, with a 4 inch crushed stone base and a 2 inch pea gravel top layer.

Layer	Footprint	Raw Volume
Base, Crushed Stone, 4 in deep	480 sq ft	160 cu ft
Top, Pea Gravel, 2 in deep	480 sq ft	80 cu ft

With a driveway project type, overage defaults to 10% and compaction to 30%. The base layer is marked compacted, so it gets both adjustments; the top layer is not marked compacted, so it only gets the overage.

Base layer (compacted): 160 x 1.10 x 1.30 = 228.8 cu ft = about 8.47 cu yd. At crushed stone's default density of 2,700 lb per cubic yard, that is about 11.44 tons.

Top layer (not compacted): 80 x 1.10 = 88 cu ft = about 3.26 cu yd. At pea gravel's default density of 2,600 lb per cubic yard, that is about 4.24 tons.

Combined total: about 11.73 cubic yards and 15.68 tons, which comes to 2 truckloads at 10 cubic yards per load, or roughly $784 at $50 per ton.

5. Understanding Your Result

The tons figure is your primary ordering number, since most gravel suppliers quote and deliver by weight. The cubic yards figure still matters for checking a supplier's volume-based quote or for smaller loads sold that way.

Both numbers are estimates. Gravel density varies meaningfully by material and source, commonly landing somewhere between about 2,400 and 3,400 pounds per cubic yard depending on particle size and moisture. Treat the calculator's defaults as reasonable starting points and confirm the exact density with your supplier before finalizing a large order. If your project has a compacted base layer, giving that layer's compaction figure a bit of room rather than cutting it close tends to work out better than ordering exactly to the calculated number. A properly compacted gravel base is also a standard part of building a durable driveway or gravel road in the first place, as outlined in the Federal Highway Administration's Gravel Roads Maintenance and Design Manual, which is why the calculator treats compaction as something you turn on for a structural base rather than a fixed add-on for every area.

6. Units and Conversions

• 1 cubic yard equals 27 cubic feet (3 ft x 3 ft x 3 ft), the conversion this calculator relies on most.
• Standard gravel commonly weighs 2,800 to 3,400 lb per cubic yard, roughly 1.4 to 1.7 tons. Pea gravel and rock sit at somewhat different points in that range due to particle size and shape.
• Depth is almost always measured in inches, while footprint is measured in feet. Mixing these up is the single most common calculation mistake for this kind of project.

7. Practical Tips

• A workable baseline depth for a decorative gravel area is about 2 to 4 inches, while driveways typically need more.
• Keep footprint in feet and depth in inches, and let the calculator handle the conversion.
• Only add a compaction allowance for material that will actually be packed down, such as a driveway or road base.
• Ask your supplier whether their price is per ton or per cubic yard, and use the matching output.
• For an irregular area, split the space into a few rectangles and circles and enter each as a separate row.

8. Common Mistakes

• Mixing units: entering depth in feet instead of inches can throw off the entire result by a factor of 12.
• Applying one density to every layer: a crushed stone base and a pea gravel top layer genuinely weigh different amounts per cubic yard, so using one figure for both under or overstates the total.
• Skipping compaction on a driveway base: ordering exactly the raw calculated volume for a base layer that will be compacted often leaves the finished job short.
• Marking a decorative layer as compacted: a top layer that is not driven on or packed down usually does not need the same allowance as a structural base, so leave its compaction toggle off.
• Rounding too early: round only the final ton or cubic yard figure, not the inputs along the way.

9. Related Calculations and Use Cases

Gravel projects often overlap with other aggregate work. If part of your project uses larger decorative stone instead of gravel, our River Rock Calculator can estimate that material using the same length, width, and depth approach.

Common real-world use cases include a gravel driveway base and top layer, a landscaping path, a patio base under pavers, a drainage trench, and filling in low spots around a new build.

10. Frequently Asked Questions

This calculator is for planning purposes only. Confirm exact density, overage, compaction, and pricing with your supplier before ordering.