Calculate Yardage Landscape: Formula & Calculator

This calculator works out the volume of soil, mulch, or other bulk material you need for a landscape project in cubic yards and cubic feet. Enter the length and width of the area in feet, the depth you want in inches, and you get the volume you need to order. It saves you from over-ordering (wasting money) or under-ordering (running out mid-project).

Formula

The basic formula for volume is the same one you use for a box:

Volume (cubic feet) = Length (ft) × Width (ft) × Depth (ft)

Since landscape depth is usually measured in inches, convert it to feet first by dividing by 12. Then, to get cubic yards, divide the cubic feet by 27 (because 1 yard = 3 feet, so 1 cubic yard = 3 × 3 × 3 = 27 cubic feet).

Combining both steps into one formula for cubic yards:

Cubic yards = (Length in feet × Width in feet × Depth in inches) / 324

Why 324? Because 12 inches per foot × 27 cubic feet per cubic yard = 324. This single number lets you plug in inches directly without converting twice.

Worked Example

Let’s use the default values from the calculator: a bed that is 40 feet long, 25 feet wide, and you want a 3-inch layer of mulch.

1. First, find the area: 40 ft × 25 ft = 1,000 square feet.
2. Convert the depth to feet: 3 in ÷ 12 = 0.25 ft.
3. Volume in cubic feet: 1,000 sq ft × 0.25 ft = 250 cubic feet.
4. Convert to cubic yards: 250 ÷ 27 = 9.26 cubic yards.

Using the combined formula: (40 × 25 × 3) / 324 = 3000 / 324 = 9.26 cubic yards. The calculator shows 9.26 yd³ and 250.0 ft³ — same result, two ways.

When to Use This Calculation

You need this calculation any time you’re buying material that is sold by volume, not by weight. Common projects include:

• Mulch for garden beds – typically 2–4 inches deep.
• Topsoil for new lawns or raised beds – usually 4–6 inches for a new lawn, 6–12 inches for a raised bed.
• Compost or soil amendment – often 1–2 inches worked into existing soil.
• Gravel or crushed stone for paths, driveways, or drainage – depth depends on use, often 2–4 inches for a path, 4–6 inches for a driveway base.
• Sand for paver bases or playgrounds – depth varies by project.

The shape of your area doesn’t have to be a perfect rectangle. For an L-shaped bed, split it into two rectangles, calculate each, and add them together. For a circular bed, use the formula for the area of a circle (π × radius²) then multiply by depth. The calculator works for any shape as long as you can find the area in square feet first.

How to Read the Result and Order Material

The calculator gives you a decimal, like 9.26 cubic yards. When you order from a landscape supplier, you’ll need to decide how to round. Here’s the practical rule:

• Bulk delivery (by the cubic yard): Round up to the next whole yard. Ordering 9.26 yards means you need 10 yards. Suppliers deliver in whole yards, and it’s better to have a little extra than to run short.
• Bagged material (by the cubic foot): Bags are usually 1, 1.5, 2, or 3 cubic feet. Divide your cubic feet total by the bag size, then round up to the next whole bag. For 250 cubic feet with 2-cubic-foot bags, that’s 125 bags exactly.

Keep in mind that volume measurements from suppliers can be approximate. Loose material settles during transport, and a “cubic yard� delivered in a truck may be a bit less than a true cubic yard once it spreads out. Ordering 5–10% extra is common for projects where exact depth matters, like a paver base.

Common Mistakes and How to Avoid Them

Three mistakes cause most yardage errors:

1. Mixing units. Always convert everything to feet (or everything to inches) before multiplying. If you measure length in feet and width in yards, you’ll get a wrong answer. Use the same unit throughout.
2. Forgetting to convert depth. Depth is usually given in inches, but the formula needs feet. Dividing by 12 is easy to skip. The combined formula (÷324) handles this for you, but only if you enter depth in inches.
3. Rounding too early. If you round the area to 1,000 sq ft (from 1,004) and then round the volume to 9.3 yards, you compound the error. Do the full calculation first, then round the final answer.

Another common issue is assuming the ground is perfectly level. If you’re filling a low spot, you need more material than the simple depth suggests. For uneven areas, measure the depth at several points and use the average, or add extra to account for settling.

Limits of the Formula

This formula assumes a flat, uniform depth. Real landscapes are rarely perfect. Here’s what the formula doesn’t account for:

• Slopes and contours: On a slope, the volume is not simply length × width × depth. You may need more material to build up the low side.
• Compaction: Some materials, like gravel and soil, compact when rolled or watered. The volume you order may settle to a smaller volume after installation. For a paver base, add 10–20% for compaction.
• Irregular shapes: The calculator works for rectangles, but for odd shapes, break them into smaller rectangles or use a more advanced method.
• Weight: The calculator gives volume, not weight. Different materials have very different densities. A cubic yard of dry topsoil weighs about 1,000–1,200 lbs, while a cubic yard of gravel weighs about 2,500–2,700 lbs. If your supplier sells by weight, you’ll need to convert using the material’s density.

For a simple, flat, rectangular bed, this formula is accurate to within a few percent — good enough for ordering. For complex projects, consider using a landscape professional or supplier’s own estimator, which may factor in compaction and waste.

Alternatives: Buying by Bag vs. Bulk

Your choice between bagged and bulk material affects how you use the calculation.

• Bulk (cubic yards): Cheapest for large areas (more than a few cubic yards). Delivered by truck and dumped in a pile. You move it yourself or pay extra for placement.
• Bags (cubic feet): Easier to handle, no delivery minimum, and you can buy exactly what you need. More expensive per cubic foot. Good for small beds or if you don’t have a wheelbarrow.

To convert the calculator’s output to bags, multiply the cubic yards by 27 to get cubic feet, then divide by the bag size (e.g., 2 cu ft). For 9.26 yards: 9.26 × 27 = 250 cu ft, ÷ 2 = 125 bags. Round up to 126 if you want a little extra.

Frequently Asked Questions

How many cubic feet are in a cubic yard?

Exactly 27. One yard is 3 feet, so a cubic yard is 3 × 3 × 3 = 27 cubic feet. This is the conversion factor you’ll use most often.

What depth of mulch do I need for a garden bed?

For most flower beds, 2–3 inches of mulch is ideal. It suppresses weeds, retains moisture, and looks neat. For a new bed or if you’re using a coarse mulch, 3–4 inches is better. More than 4 inches can smother plant roots and encourage pests.

How do I calculate for a circular area?

Find the radius (half the diameter), square it, multiply by π (3.1416) to get the area in square feet. Then multiply by the depth in feet (or use the calculator with length = width = diameter, but that overestimates by about 21% for a circle). Better to do the area separately and then use the calculator with length = area / width, or just multiply area × depth / 27.

Why is my supplier asking for weight, not volume?

Some materials, especially soils and mulches, are sold by weight because moisture content changes volume. A cubic yard of dry mulch weighs about 400–600 lbs, but wet mulch can weigh more. Ask your supplier for the density of the specific material, then convert: weight = volume (cu yd) × density (lbs/cu yd).

Should I order extra material?

Yes, for most projects, order 5–10% extra. This covers settling, spillage, and uneven areas. For paver bases or any project where you need a specific compacted depth, add 10–20% to account for compaction.

Can I use this for concrete or asphalt?

Yes, but concrete is usually ordered in cubic yards, and the calculator works the same. However, concrete is sold by the cubic yard with a minimum order (often 1 yard), and you must account for forms, waste, and depth variations. For concrete, always confirm with the supplier or a contractor.

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in l | Lawn length | ft | 40 | 0 | 100000
in w | Lawn width | ft | 25 | 0 | 100000
in d | Depth | in | 3 | 0 | 120
out yd | Volume | yd³ | l * w * d / 324 | 2
out ft3 | Volume | ft³ | l * w * d / 12 | 1