How Much Fill Dirt Do I Need?

What is a cubic yard?

A cubic yard is a block of material 3 feet long, 3 feet wide and 3 feet tall. That works out to 27 cubic feet. Dirt, gravel and fill are all sold by the yard or by the ton, so it's the number you'll want before you call anyone.

The math

Measure the area you need to fill in feet, and the depth in inches. Multiply length by width by depth in feet, then divide by 27. Or plug your numbers into the calculator below.

For example, filling an area 100 feet long and 12 feet wide by 6 inches takes about 22 cubic yards.

Why you always need more than the math says

Fill dirt settles and packs down once it's placed and compacted, especially when it's going under a pad, slab or driveway. A pile that looks like plenty in the truck ends up lower once it's rolled. The amount of shrink depends on the material and how hard it's compacted, so plan on ordering extra.

Not all fill is the same

• Fill dirt is subsoil for raising grade and filling low spots. It's the cheapest option but it doesn't grow grass well on top.
• Topsoil goes on last, a few inches deep, where you want grass or a garden.
• Structural fill is compactable material for anything that will carry weight, like a building pad, slab or driveway. It goes in thin layers, each one compacted before the next.

Under a building, the kind of fill and how it's compacted matters more than the amount. Loose fill under a slab or pad settles, and the cracks show up later.

Placing it right

Dumping fill is easy. Placing it so it stays put is the real job. It should go down in layers, get compacted as it goes, and be shaped so water drains away from buildings instead of toward them.

Need fill placed?

We deliver and place fill, build up low spots, and cut and compact building pads across Ravalli and Missoula counties. Tell us what you're building on it and we'll recommend the right material and how much.