How Much Fill Dirt Do I Need? A Cubic Yard Guide
Fill dirt is sold by the cubic yard, but jobs get measured in feet and inches, so the first question on every project is the same: how many yards do I order? This guide gives you the exact formula, a fully worked example with the arithmetic shown, the compaction allowance that trips up most estimates, and a quick way to size your truck loads. When you want the number in seconds instead of by hand, our soil calculator does the same math for you.
Key takeaways
- One cubic yard equals 27 cubic feet. That single conversion drives the whole estimate.
- Cubic yards = (length in feet x width in feet x depth in feet) divided by 27. Convert depth in inches to feet by dividing by 12.
- Compacted or engineered fill needs more loose material than the void it fills, commonly on the order of 15 to 25 percent more, because the material settles when it is compacted.
- A typical tandem dump truck hauls roughly 10 to 16 cubic yards per load, which varies by truck and by DOT axle limits.
- Estimate before you order so you buy the right amount once. Our soil calculator runs the math instantly.
The formula
Every fill estimate starts with volume, and volume is just length times width times depth. The only catch is units. Dirt is priced and delivered by the cubic yard, but your site is measured in feet and inches, so you have to convert. Since one cubic yard is 27 cubic feet, you take your volume in cubic feet and divide by 27. If you would rather skip it entirely, our soil calculator takes your dimensions and returns yards, including the compaction allowance, in one step.
The depth conversion is where estimates go wrong most often. Fill depth is almost always called out in inches, and inches have to become feet before they enter the formula. Divide the inches by 12. Eight inches of fill is 8 / 12, which equals 0.667 feet. Use that decimal in the volume calculation, not the raw inch number.
A worked example
Say you are raising a building pad that measures 60 feet by 40 feet and you need 8 inches of fill across the whole area. Here is the full calculation, step by step, with real numbers.
| Step | Example |
|---|---|
| 1. Convert depth to feet | 8 in / 12 = 0.667 ft |
| 2. Multiply the dimensions | 60 ft x 40 ft x 0.667 ft = 1,600 cubic feet |
| 3. Convert to cubic yards | 1,600 / 27 = 59.26 cubic yards (in place) |
| 4. Add a compaction allowance (20%) | 59.26 x 1.20 = 71.11, round to about 71 cubic yards to order |
| 5. Estimate truck loads (at ~12 cy per load) | 71 / 12 = about 6 loads |
So a 59 cubic yard void becomes about 71 cubic yards of loose fill ordered, delivered in roughly 6 typical loads. The two numbers people forget are the 27 divisor and the compaction bump. Miss either one and you end up short.
The same three steps handle any shape. A utility trench 200 feet long, 3 feet wide, and 4 feet deep is 200 x 3 x 4 = 2,400 cubic feet, divided by 27 = 88.9 cubic yards in place, or about 107 cubic yards ordered once you add a 20 percent compaction allowance. The depth is already in feet here, so there is no inch conversion; the one constant that never changes is the 27.
The compaction allowance
Loose fill takes up more space in the truck than it does once it is placed and compacted in the ground. When a pad or trench is built to spec, the material is spread in lifts and compacted, and it loses volume in the process. That means the void you measured needs more loose material than its plain cubic-yard figure. A planning allowance commonly on the order of 15 to 25 percent extra covers it. The exact figure depends on the material and the compaction effort, so treat it as a planning buffer, not a guarantee. For graded sites with cut and fill, our earthwork calculator handles the balance, and for building pads our pad calculator sizes the fill and the compacted depth together.
Estimating truck loads
Once you have your ordered yards, dividing by the truck capacity tells you the load count and helps you plan site access and timing. A typical tandem dump truck hauls roughly 10 to 16 cubic yards, which varies by the specific truck and by DOT weight limits. Using the worked example above, 71 yards is about 7 loads at 10 yards each, or closer to 5 loads at 16 yards each. We confirm the exact capacity for your delivery when we quote.
- Measure length, width, and depth in the same units, then convert depth from inches to feet.
- Always divide cubic feet by 27 to reach cubic yards.
- Add the compaction allowance before you order, not after.
- Confirm the material. Fill dirt raises grade, while select fill is the engineered, compaction-friendly option for pads and structural areas.
Estimating before you order matters because dirt is heavy, freight is most of the cost, and a second short delivery wastes a whole trip. Get the number right once. Our soil calculator takes your dimensions, applies the compaction allowance, and returns the yards to order plus an estimated load count, so you can quote a job or place an order with confidence.
Fill dirt volume FAQ
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Enter your dimensions and let our calculator handle the conversion, the compaction allowance, and the load count. Then send us the numbers for a delivered quote across DFW, Austin, San Antonio, and Houston.