Fill Dirt Calculator

Fill dirt calculator for estimating cubic yards to order for a leveling or backfill job

This fill dirt calculator is for one specific decision: how much fill dirt to order when you are filling a rectangular area to an average depth. Typical uses include leveling a section of yard, raising a low spot, backfilling alongside a foundation, or filling a trench or hole after work is finished. The output is designed around how suppliers sell material, so the primary result is cubic yards to order, with optional weight and cost estimates to help you plan delivery and budget.

To use it, measure the length and width of the area in feet, then estimate the average depth of fill in inches. “Average” matters because most real sites are not perfectly flat. If the depth varies, take a few measurements and use a simple average. The calculator first computes the compacted volume (the space you want to fill), then adds an allowance percentage to estimate the loose volume you should order. This allowance helps cover compaction, minor grading, and inevitable unevenness.

The results include multiple units so you can sanity-check your plan. Cubic yards are the ordering unit for most bulk fill dirt suppliers. Cubic feet can help you verify the math against your measurements. Cubic meters are included for users working in metric. If you add an estimated density, you also get tons, which is useful when a supplier prices by weight or when you need to confirm truck capacity. If you add a price per cubic yard, you get a simple cost estimate based on the order quantity.

Assumptions and how to use this calculator

• This calculator assumes a rectangular area with reasonably straight sides (length × width) and a single average depth.
• Depth is entered in inches and converted to feet internally; small depth changes can have a big impact on volume.
• The “extra allowance” percentage estimates additional loose material needed for compaction, settling, and light grading.
• The tons estimate depends on density, which varies by moisture and soil type; the default is a general planning value, not a lab measurement.
• This tool is for fill dirt only and does not attempt to model topsoil, mulch, gravel, sand, or engineered base layers.

Common questions

Why does the calculator add an extra allowance percentage?

Fill dirt is delivered “loose” and usually ends up more compact once you spread, water, tamp, or drive equipment over it. Even without heavy compaction, material settles into low spots and gets redistributed during grading. The allowance is a practical buffer so you do not come up short. If you are doing a very light fill with minimal compaction, a smaller allowance can be reasonable. If you are filling deeper areas or expect serious compaction, a larger allowance is safer.

What if my depth is not the same everywhere?

Use an average depth. Take a few depth readings across the area, add them up, and divide by how many readings you took. If the variation is extreme (for example, one side is near zero and the other side is very deep), splitting the job into two rectangles and calculating each separately is more accurate than using one average for the whole area.

How accurate is the tons estimate?

It is a planning estimate only. Soil weight changes with moisture, compaction, and composition. Dry, sandy soil can be lighter, while wet clay can be significantly heavier. If your supplier sells by weight or your access route limits truck size, ask the supplier what density they assume for the material they deliver and use that value in the Advanced section.

Do I need to round up the cubic yards I order?

Usually yes. Suppliers often deliver in half-yard or quarter-yard increments, and you cannot easily “un-order” a fraction that you come up short on. The calculator provides a rounded-up order quantity to the nearest quarter yard to reflect typical ordering behavior. If your supplier has different minimums, use the exact cubic yards as a base and round according to their rules.

When should I not use fill dirt for the top layer?

Fill dirt is typically used as a base or bulk volume, not as the final surface layer for planting. For lawns, gardens, and landscaping, a top layer of quality topsoil is usually needed for better drainage and plant health. This calculator intentionally does not estimate topsoil needs because it is a different material choice with different thickness and quality considerations.