One cubic yard of dirt typically covers an area of about 324 square feet if spread one inch deep. The exact area a “yard of dirt” covers depends entirely on how thick you spread it. A “yard of dirt” usually means a cubic yard, which is a measure of volume, like how much space something takes up. Area is a flat measurement, like the size of a floor. You can spread the same amount of dirt over a large area very thinly, or over a small area very thickly.
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Getting the Right Amount of Dirt
Buying dirt for a project, like filling a garden bed or leveling a lawn, needs careful thought. You don’t want too little and have to order more. You also don’t want too much and have piles left over. Knowing how much ground a certain amount of dirt covers is key. This amount is often sold by the “yard.” But what does that mean? And how do you figure out how much area it will cover for your job?
What a “Yard” Means for Dirt
When you hear “a yard of dirt” from a soil company, they almost always mean a cubic yard. This is a standard way to measure materials like soil, gravel, and mulch.
Think of a cubic yard like a box. This box is 3 feet long, 3 feet wide, and 3 feet tall.
- It’s 3 feet by 3 feet by 3 feet.
- If you multiply these numbers (3 * 3 * 3), you get 27.
- So, one cubic yard holds the same amount as 27 smaller boxes that are each 1 foot long, 1 foot wide, and 1 foot tall (these are called cubic feet).
- One cubic yard = 27 cubic feet.
This 27 cubic feet is the total amount of dirt you have in one yard. The task now is to see how much flat ground (area) this amount of dirt will cover when spread out.
Why Depth Matters a Lot
Imagine you have a bucket of sand. You can pour it out to make a big, thin circle on the ground. Or, you can pour it to make a small, tall pile. The amount of sand is the same, but the area it covers is very different.
Dirt works the same way. The coverage area of a cubic yard depends completely on how thick you spread it. This thickness is called the depth.
- If you spread the dirt very thin (maybe just one inch deep), it will cover a large area.
- If you spread the dirt very thick (maybe one foot deep), it will cover a much smaller area.
This is why simply asking “How much area does a yard of dirt cover?” needs more information. You must also know “How deep do you want the dirt?”
Seeing the Numbers: Coverage by Depth
Let’s look at specific numbers. We know one cubic yard is 27 cubic feet. We want to find out how much area (in square feet) this volume covers at different depths.
To do this, we use a simple idea:
Volume = Area × Depth
So, to find the Area, we can flip the formula:
Area = Volume / Depth
We have the volume (27 cubic feet). We need to use the depth, but it must be in feet to match the cubic feet volume. Depths for dirt projects are often measured in inches (like 1 inch, 3 inches, 6 inches). We need to change these inches into feet.
- There are 12 inches in 1 foot.
- So, 1 inch is 1/12 of a foot.
- 2 inches is 2/12 of a foot.
- 3 inches is 3/12 of a foot (which is 1/4 or 0.25 feet).
- And so on.
Now we can figure out the square feet per yard of soil for common depths. This is where we get the dirt coverage per inch deep or for other depths.
Figuring Out Coverage: The Simple Math
Let’s calculate the coverage for different depths using the formula: Area (sq ft) = 27 cubic feet / Depth (in feet).
Coverage at One Inch Deep
- Depth = 1 inch.
- Convert inches to feet: 1 inch = 1/12 feet.
- Area = 27 cubic feet / (1/12 feet)
- Area = 27 * 12 square feet
- Area = 324 square feet.
So, one cubic yard of dirt covers about 324 square feet when spread one inch deep. This number, 324 sq ft per inch, is a very handy one to remember for cubic yard coverage.
Coverage at Two Inches Deep
- Depth = 2 inches.
- Convert inches to feet: 2 inches = 2/12 feet = 1/6 feet.
- Area = 27 cubic feet / (1/6 feet)
- Area = 27 * 6 square feet
- Area = 162 square feet.
One cubic yard covers about 162 square feet when spread two inches deep. As you see, doubling the depth cuts the coverage area in half.
Coverage at Three Inches Deep
- Depth = 3 inches.
- Convert inches to feet: 3 inches = 3/12 feet = 1/4 feet = 0.25 feet.
- Area = 27 cubic feet / (1/4 feet)
- Area = 27 * 4 square feet
- Area = 108 square feet.
One cubic yard covers about 108 square feet when spread three inches deep. This is a common depth for topdressing a lawn or starting a new garden bed.
Coverage at Four Inches Deep
- Depth = 4 inches.
- Convert inches to feet: 4 inches = 4/12 feet = 1/3 feet (about 0.333 feet).
- Area = 27 cubic feet / (1/3 feet)
- Area = 27 * 3 square feet
- Area = 81 square feet.
One cubic yard covers about 81 square feet when spread four inches deep. This depth is good for building up beds or fixing low spots.
Coverage at Six Inches Deep
- Depth = 6 inches.
- Convert inches to feet: 6 inches = 6/12 feet = 1/2 feet = 0.5 feet.
- Area = 27 cubic feet / (1/2 feet)
- Area = 27 * 2 square feet
- Area = 54 square feet.
One cubic yard covers about 54 square feet when spread six inches deep. This is often the depth needed for new garden beds or filling larger holes. This calculation shows how deep does one yard of dirt cover a specific area, or vice versa.
Coverage at Twelve Inches Deep (One Foot)
- Depth = 12 inches.
- Convert inches to feet: 12 inches = 1 foot.
- Area = 27 cubic feet / (1 foot)
- Area = 27 square feet.
One cubic yard covers about 27 square feet when spread one foot deep. This makes sense, as one cubic yard is 3 ft x 3 ft x 3 ft = 27 cubic feet. If you spread it 1 foot deep, the area covered is 27 square feet (3 ft x 9 ft, or any shape totaling 27 sq ft).
Quick Table of Coverage
Here’s a table showing the approximate calculating dirt coverage results for different common depths:
| Desired Depth (Inches) | Desired Depth (Feet) | Area Covered by 1 Cubic Yard (Square Feet) |
|---|---|---|
| 1 inch | 1/12 ft (≈ 0.083 ft) | 324 sq ft |
| 2 inches | 2/12 ft (≈ 0.167 ft) | 162 sq ft |
| 3 inches | 3/12 ft (0.25 ft) | 108 sq ft |
| 4 inches | 4/12 ft (≈ 0.333 ft) | 81 sq ft |
| 6 inches | 6/12 ft (0.5 ft) | 54 sq ft |
| 12 inches (1 foot) | 1 ft | 27 sq ft |
This table gives you a quick reference for the coverage area of a cubic yard at various depths.
You might also hear about square yards. One square yard is 3 feet by 3 feet, which is 9 square feet. To find the coverage in square yards, you just divide the square footage by 9.
- 1 inch deep: 324 sq ft / 9 sq ft/sq yard = 36 square yards.
- 3 inches deep: 108 sq ft / 9 sq ft/sq yard = 12 square yards.
- 6 inches deep: 54 sq ft / 9 sq ft/sq yard = 6 square yards.
- 12 inches deep: 27 sq ft / 9 sq ft/sq yard = 3 square yards.
This tells you the square yards per cubic yard at different depths.
More Than Just Math: Things That Change Coverage
The numbers above are based on perfect math with neat, level dirt. In the real world, things are a little different. Several factors can affect how much area your cubic yard of dirt actually covers.
How Soil Packs Down (Compaction)
When dirt is loaded into a truck or bag, it’s often loose. When you spread it out and walk on it, water it, or let it settle over time, it gets denser. This is called compaction.
- Loose dirt takes up more space (volume) than compacted dirt.
- When you spread out a cubic yard of loose dirt, and it then settles or gets packed down, its volume shrinks a bit.
- This means it might not quite cover the area calculated, or you might need a little more dirt to reach your desired final depth after settling.
For example, a soil volume calculator might give you a number based on loose fill. But after spreading and settling, you might find the depth is slightly less than planned. It’s often wise to add a little extra to your estimate, maybe 5-10%, to account for this.
Different Kinds of Dirt Act Differently
Not all dirt is the same.
- Sandy soils drain fast and don’t compact as much.
- Clay soils can be very dense and might hold their shape differently.
- Compost or topsoil blends often have a lot of organic matter and can be quite fluffy when delivered, then settle more than plain soil.
The weight and structure of the specific type of dirt can slightly affect how it spreads and settles, changing the actual cubic yard coverage.
Bumpy Ground Needs More Dirt
If the area you are filling is not flat and level, you will need more dirt than the simple area calculation suggests.
- Filling a low spot requires extra dirt just for that dip.
- Trying to make a very uneven area level will use a lot more material in the low parts.
The calculations assume you are spreading the dirt evenly over a perfectly flat surface. If your ground is bumpy, you should factor that in. You might need to add extra volume to fill the lowest parts up to the average level before spreading the final layer.
Planning Your Project: Estimating Soil Needs
Okay, now you know how much area a cubic yard covers at different depths and what can change that. How do you figure out how much dirt you need for your project? This is called estimating soil needs. It involves the reverse process: starting with the area you want to cover and the depth you need, then calculating the volume of dirt required.
Here are the steps for calculating dirt coverage needed (or rather, the dirt volume needed for an area):
1. Measure Your Area (Square Feet!)
First, find the size of the area you want to cover with dirt. Measure the length and width of the space in feet.
- If it’s a rectangle or square: Area = Length × Width.
- Example: A space 20 feet long and 10 feet wide has an area of 20 * 10 = 200 square feet.
- If it’s a circle: Find the radius (distance from the center to the edge) in feet. Area = π (pi, about 3.14) × radius × radius.
- Example: A circular bed with a radius of 5 feet has an area of 3.14 * 5 * 5 = 3.14 * 25 = 78.5 square feet.
- For irregular shapes: Break the shape down into smaller rectangles, squares, or circles. Calculate the area of each small piece and add them together.
Get the area in square feet. This is your base number.
2. Pick Your Depth
Next, decide how deep you need the dirt to be. This depends on your project:
- Topdressing a lawn: Maybe 1/2 inch to 1 inch.
- Starting a new grass area (sod or seed): Often 3-6 inches of good topsoil.
- Filling a raised garden bed: Might be 6 inches, 12 inches, or even more, depending on the bed’s height.
- Leveling a bumpy yard: The needed depth will vary, so you might estimate an average depth or calculate volume for specific low spots.
Measure or decide on your desired depth in inches.
3. Using a Soil Volume Calculator (Or Simple Math)
Now you have the area in square feet and the depth in inches. You need to find the volume in cubic yards. This is a volume to area conversion dirt process.
You can use an online soil volume calculator, which makes it easy. You plug in your area in square feet and your depth in inches, and it tells you how many cubic yards you need.
Or, you can do the math yourself using the numbers we learned earlier.
- Remember that 1 cubic yard covers 324 square feet at a 1-inch depth.
- This means for every 324 square feet you want to cover 1 inch deep, you need 1 cubic yard.
- What if you want a different depth? For a depth of D inches, the area covered by 1 cubic yard is 324 / D square feet.
- So, if you have an area of A square feet and want a depth of D inches, the number of cubic yards needed is:
(Area in sq ft / 324 sq ft per yard at 1 inch) * Depth in inches
Cubic Yards = (A / 324) * D
Cubic Yards = (A * D) / 324
Let’s try an example calculation.
Step-by-Step Calculation Example
- Your Area: You want to cover a rectangular area that is 30 feet long and 15 feet wide.
- Area = 30 ft * 15 ft = 450 square feet.
- Your Depth: You want the dirt to be 4 inches deep.
- Calculate Yards Needed:
- Using the formula: Cubic Yards = (Area * Depth) / 324
- Cubic Yards = (450 sq ft * 4 inches) / 324
- Cubic Yards = 1800 / 324
- Cubic Yards ≈ 5.56
So, for this project, you would need about 5.56 cubic yards of dirt.
Since you usually can’t buy parts of a cubic yard easily, you would likely round up to the nearest half or whole yard when ordering. In this case, you’d probably order 6 cubic yards. It’s better to have a little extra than not enough.
Putting It All Together: Real-World Examples
Let’s apply this to a few common projects to show the estimating soil needs process.
Topping Up a Flower Bed
Imagine you have a flower bed that is 25 feet long and 4 feet wide. You want to add just a thin layer of fresh topsoil, about 2 inches deep, to give your plants a boost.
- Area: 25 ft * 4 ft = 100 square feet.
- Depth: 2 inches.
- Yards Needed: Using the formula (Area * Depth) / 324
- Cubic Yards = (100 sq ft * 2 inches) / 324
- Cubic Yards = 200 / 324
- Cubic Yards ≈ 0.62
You would need about 0.62 cubic yards. If your supplier sells half yards, you might order 0.5 or 1 cubic yard depending on if you want a little extra or not. If they only sell whole yards, you’d order 1 cubic yard.
Laying New Sod
Suppose you just finished a building project, and you have a large rectangle area ready for a new lawn. The area is 50 feet long and 30 feet wide. You need to bring in 4 inches of good topsoil before laying sod.
- Area: 50 ft * 30 ft = 1500 square feet.
- Depth: 4 inches.
- Yards Needed: Using the formula (Area * Depth) / 324
- Cubic Yards = (1500 sq ft * 4 inches) / 324
- Cubic Yards = 6000 / 324
- Cubic Yards ≈ 18.52
For this large area needing 4 inches of soil, you’d need around 18.5 cubic yards. You would likely order 19 or maybe even 20 cubic yards to be safe, considering potential unevenness or settling. This clearly shows the dirt coverage per inch deep multiplied by the number of inches needed.
Filling a Raised Garden Bed
You built a raised garden bed that is 8 feet long, 4 feet wide, and 1 foot tall. You want to fill it completely with a soil mix.
- Area: 8 ft * 4 ft = 32 square feet.
- Depth: 1 foot. Since our formula uses inches, convert 1 foot to 12 inches.
- Depth (in inches): 12 inches.
- Yards Needed: Using the formula (Area * Depth) / 324
- Cubic Yards = (32 sq ft * 12 inches) / 324
- Cubic Yards = 384 / 324
- Cubic Yards ≈ 1.19
You would need about 1.2 cubic yards. You would probably order 1.5 or 2 cubic yards depending on availability and how full you want the bed to be (some people leave a few inches empty at the top). Notice that for a 12-inch depth, the area covered by 1 cubic yard is 27 sq ft. Our bed is 32 sq ft, slightly larger than 27 sq ft, so it makes sense that we need a little more than 1 cubic yard.
Getting the Dirt Delivered: Tips
When you order dirt by the cubic yard, it usually comes in a dump truck. Here are a few practical tips:
- Delivery Spot: Choose a place for the truck to dump the dirt that is easy for the truck to reach and where the dirt will be out of the way but still close to your project area. Remember, once it’s dumped, moving it is hard work!
- Space Needed: A dump truck needs a good amount of space to maneuver and lift its bed. Make sure there are no overhead wires, trees, or low structures.
- Tarps: If you’re worried about killing the grass underneath or want to make cleanup easier, lay down a large tarp before the dirt is dumped.
- Check the Load: When the truck arrives, quickly check that the amount looks about right based on what you ordered. While hard to measure volume exactly by eye, a half load should look roughly half the size of a full load.
- Moisture: Dirt can be heavier and look like less volume if it’s very wet. Ask your supplier if their yards are measured loose or wet. This can affect the actual amount you get.
Understanding the volume to area conversion dirt principle and doing the simple math helps you order correctly, saving you time and money.
Important Takeaways
- A “yard of dirt” means one cubic yard, which is 27 cubic feet.
- The area one cubic yard covers depends entirely on the depth you spread it.
- A simple way to figure out coverage is knowing that 1 cubic yard covers 324 square feet when spread 1 inch deep (dirt coverage per inch deep).
- To find coverage at other depths, divide 324 by the number of inches deep you want (e.g., 324 / 3 inches = 108 sq ft for 3 inches deep). This is your cubic yard coverage number for that depth.
- To figure out how much dirt you need ( estimating soil needs or calculating dirt coverage volume), measure your area in square feet and decide your depth in inches. Then use the formula: Cubic Yards = (Area in sq ft * Depth in inches) / 324.
- Always think about settling and uneven ground. Ordering a little extra (maybe 10%) is often a good idea.
- Remember the coverage area of a cubic yard changes inversely with depth: deeper means less area covered, shallower means more area covered.
- You can easily convert square feet coverage to square yards per cubic yard by dividing the square footage by 9.
- Use a soil volume calculator online if you prefer not to do the math by hand.
Knowing these simple facts helps you confidently plan your outdoor projects involving dirt, topsoil, or compost.
Frequently Asked Questions (FAQ)
Q: What is a cubic yard in simple terms?
A: A cubic yard is like a giant box that is 3 feet wide, 3 feet long, and 3 feet high. It holds the amount of dirt from inside that box. It’s a measure of volume.
Q: How much area will one cubic yard cover at a depth of 3 inches?
A: One cubic yard will cover about 108 square feet when spread 3 inches deep. We found this by dividing the 1-inch coverage (324 sq ft) by 3 inches (324 / 3 = 108).
Q: How do I calculate how many cubic yards of dirt I need?
A: First, measure the area you want to cover in square feet (Length x Width). Then, decide on your depth in inches. Multiply the area by the depth, and then divide that number by 324. This gives you the number of cubic yards needed. Example: (Area in sq ft * Depth in inches) / 324.
Q: Does the type of dirt change how much area it covers?
A: The core math (27 cubic feet = 1 cubic yard) is always true. However, different types of dirt (like sand vs. clay vs. compost) can settle or compact differently after you spread them. This means the final depth might be slightly less than planned, making it seem like it covered a little less area at that final depth. It’s a small difference for most home projects.
Q: If I need 6 inches of dirt, how many square feet does one yard cover?
A: If you need 6 inches of dirt, one cubic yard covers about 54 square feet. We got this by taking the 1-inch coverage (324 sq ft) and dividing by 6 inches (324 / 6 = 54).
Q: Is there an easy online tool to help calculate this?
A: Yes, searching for “soil volume calculator” online will show you many free tools where you can enter your length, width, and depth, and it will tell you how many cubic yards you need. These tools do the volume to area conversion dirt math for you.
Q: How much is a square yard?
A: A square yard is a flat area that is 3 feet long and 3 feet wide. It covers 9 square feet (3 ft * 3 ft = 9 sq ft).
Q: How many square yards does a cubic yard cover at 1 inch deep?
A: A cubic yard covers 324 square feet at 1 inch deep. Since 1 square yard is 9 square feet, it covers 324 / 9 = 36 square yards at 1 inch deep. This shows the square yards per cubic yard relationship.
Q: Why is my dirt pile smaller after it rains?
A: Rain helps the dirt settle and compact. The water fills air pockets, and the weight of the water and the dirt presses it down. The total amount of dirt is still the same (one cubic yard by weight if it was dry), but it takes up less space (volume) because it’s denser.