Gravel Calculator in Yards: Volume & Cost

This gravel calculator works out how many cubic yards of gravel you need for a rectangular area, based on the length, width, and depth you enter. You input the three dimensions in feet and inches (or meters), and it returns the volume in cubic yards, plus an estimate of the total weight in tons. The calculator uses the standard formula for volume and the typical density of gravel to give you a number you can order from a supplier with confidence.

Formula

The core formula converts the three dimensions into a volume in cubic feet, then divides by 27 (the number of cubic feet in a cubic yard) to get cubic yards:

Cubic yards = (Length (ft) × Width (ft) × Depth (ft)) / 27

Since depth is usually given in inches, you first convert it to feet by dividing by 12. The variables are:

• Length – the longer side of the area, in feet.
• Width – the shorter side, in feet.
• Depth – how thick the gravel layer will be, in inches (converted to feet).
• 27 – the number of cubic feet in one cubic yard (3 ft × 3 ft × 3 ft).

For the weight estimate, the calculator multiplies the cubic yards by 1.4, which is the approximate density of loose gravel in tons per cubic yard. Real gravel density ranges from about 1.2 to 1.7 tons per cubic yard depending on the type and moisture content, so treat the weight as an estimate.

Worked Example

Using the default values from the calculator: a 20-foot-long, 10-foot-wide area with a 4-inch-deep layer of gravel.

1. Convert depth to feet: 4 inches ÷ 12 = 0.333 feet.
2. Calculate volume in cubic feet: 20 ft × 10 ft × 0.333 ft = 66.6 cubic feet.
3. Convert to cubic yards: 66.6 ÷ 27 = 2.47 cubic yards.
4. Estimate weight: 2.47 × 1.4 = 3.46 tons.

The calculator shows 2.47 cubic yards and 3.46 tons for these inputs. That matches what a supplier would deliver for a small patio base or a walkway.

When to Use This Calculator

Use it any time you need to order gravel for a project that has a roughly rectangular footprint. Common situations include:

• Building a gravel driveway or parking pad.
• Laying a base for a shed, patio, or walkway.
• Filling a garden path or a trench for drainage.
• Estimating how much crushed stone you need for a French drain.

The calculator works best for flat, uniform areas. If your project is an irregular shape, divide it into rectangles, calculate each one, and add the results. For a circular area (like a fire pit base), you would need a different formula: π × radius² × depth, then convert to cubic yards.

How to Choose the Right Depth

The depth you need depends entirely on the project. There is no single universal number, but here are typical guidelines:

• 2–3 inches – decorative gravel for a walkway or mulch replacement.
• 4 inches – base layer for a patio or shed foundation.
• 6–8 inches – driveway gravel, especially if vehicles will drive on it.
• 12 inches or more – heavy-duty drainage or road base in poor soil.

If you are unsure, ask your local supplier or a contractor. Going too shallow means the gravel shifts and exposes the ground; going too deep wastes money and may make the surface unstable.

Common Mistakes and How to Avoid Them

The most frequent error is mixing units. Always convert everything to the same unit before calculating. Here are the top pitfalls:

• Forgetting to convert depth from inches to feet. A 4-inch depth is 0.333 feet, not 4 feet. This mistake makes the result 12 times too large.
• Using square yards instead of cubic yards. Square yards measure area, not volume. You need depth to get cubic yards.
• Rounding too early. If you round 0.333 to 0.3, you lose about 10% of your volume. Keep at least three decimal places until the final answer.
• Ordering by weight instead of volume. Suppliers sell gravel by the cubic yard or by the ton. Know which one you are ordering. If you order by the ton, use the weight estimate and add 10–15% for compaction and spillage.

Another common misconception is that one cubic yard covers 100 square feet at 3 inches deep. Actually, 1 cubic yard covers 108 square feet at 3 inches (since 1 yard = 36 inches, and 36/3 = 12, so 1 yd³ covers 12 × 9 = 108 ft²). The difference is small, but it adds up on large projects.

Understanding the Result and Ordering

Your result in cubic yards is the volume of gravel you need to fill the space exactly to the depth you specified. In practice, you should order slightly more because gravel compacts and settles. A common rule is to add 5–10% for a walkway and 10–15% for a driveway. For example, if the calculator says 2.47 cubic yards, order 2.7 or 3 cubic yards.

When you call a supplier, they will ask whether you want it delivered or you will pick it up. Delivery is usually charged separately, and they may have a minimum order. You can also ask for the gravel by weight: multiply the cubic yards by the density (typically 1.4 tons/yd³) to get tons. A standard dump truck carries about 10–14 cubic yards, so for a small project you might need a pickup truck and multiple trips.

Gravel Types and What They Cost

The calculator gives you volume, but the type of gravel affects both weight and price. Common types include:

• Crushed stone – angular pieces, good for driveways and bases. Density around 1.4 tons/yd³.
• Pea gravel – small, rounded stones, good for paths and play areas. Density around 1.3 tons/yd³.
• Bank gravel – a mix of sand and stone, often used as a base. Density around 1.5 tons/yd³.
• River rock – larger, smooth stones, decorative. Density around 1.6 tons/yd³.

Prices vary by region and availability, but you can generally expect crushed stone to be the cheapest and river rock the most expensive. The calculator’s weight estimate of 1.4 tons/yd³ is a reasonable middle ground for most projects.

Frequently Asked Questions

How many square feet does a cubic yard of gravel cover?
It depends on depth. At 3 inches deep, one cubic yard covers 108 square feet. At 4 inches deep, it covers 81 square feet (since 27 / (4/12) = 81). At 6 inches deep, it covers 54 square feet. Use the formula: square feet = 27 / (depth in feet).

How do I convert cubic yards to tons?
Multiply the cubic yards by the density of the gravel in tons per cubic yard. For most gravel, use 1.4. So 2 cubic yards × 1.4 = 2.8 tons. If you know the exact density from your supplier, use that number.

What if my area is not a perfect rectangle?
Break it into rectangles, calculate each one separately, and add the totals. For a triangle, use (base × height / 2) for the area, then multiply by depth and divide by 27. For a circle, use π × radius² for the area, then multiply by depth and divide by 27.

Should I order extra gravel?
Yes, order 5–15% more than the calculated volume. Gravel compacts and settles, and you may have uneven spots that need filling. It is cheaper to order a little extra than to pay for a second delivery.

Can I use this calculator for sand or topsoil?
Yes, the volume calculation is the same for any bulk material. The weight estimate will be different, though. Sand weighs about 1.2 tons per cubic yard, and topsoil weighs about 1.1 tons per cubic yard. Adjust the density in your own calculations if you need weight.

Why is the weight estimate different from what the supplier quoted?
Gravel density varies with moisture, stone size, and compaction. A supplier’s quote may be based on a different density or on the actual weight of the load. Always confirm the weight with the supplier if it matters for your project.

Related

• Drywall Calculator Material: How Much You Need
• Drywall Adhesive Calculator: How Much You Need
• Drywall Board Calculator: Sheets & Cost

in length | Length | ft | 20 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 4 | 0
out cubic_yards | Cubic yards needed | yd³ | (length * width * (depth / 12)) / 27 | 2
out tons | Estimated weight | tons | cubic_yards * 1.4 | 2