How the dirt calculator works
The calculator follows the same steps an excavation contractor or soil yard uses when you phone for a quote:
- Measure the space. Length × width for a rectangle, 3.1416 × radius² for a circle. A hole or trench is length × width × depth, all in feet.
- Turn it into volume. Area in square feet × depth in feet. Six inches is 0.5 ft, so a 20 × 10 ft area at 6 inches holds 200 × 0.5 = 100 cubic feet.
- Convert to cubic yards. Divide cubic feet by 27, because a cubic yard is 3 ft × 3 ft × 3 ft. 100 ÷ 27 = 3.70 cubic yards.
- Add the compaction allowance. 3.70 × 1.15 = 4.26 cubic yards of loose dirt to order.
- Weigh it and load it. Fill dirt at about 2,200 lb per yard is 4.26 × 1.1 = 4.69 tons, which is one load in a 5-yard single-axle dump truck.
cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27 × (1 + allowance)
For an odd-shaped area, split it into rectangles and circles, run each one, and add the cubic yards together. For a hole with sloped sides, measure the width halfway down.
How deep do you need the dirt?
| Job | Typical depth of fill | Notes |
|---|---|---|
| Topping up a flower bed or low patch | 2–4 in | Small jobs are often cheaper in bags than a delivery. |
| Filling a dip or low spot in the yard | 4–12 in | Fill in layers and tamp each one. See the fill dirt calculator. |
| Building up a slope away from the house | Tapers from about 6 in to 0 | Use the wedge mode on the yard grading calculator. |
| Backfilling a trench for a pipe or cable | Full trench depth, often 1–4 ft | See the backfill calculator. |
| Filling in a swimming pool | The whole pool, often 3–8 ft | See the pool fill-in calculator. |
| Raising a building pad or shed base | 6–24 in | Structural fill may need to meet an engineer’s spec. |
How far does a cubic yard of dirt go?
These are the measured volumes, before the compaction allowance. Divide 324 by the depth in inches to get the coverage of one cubic yard at any depth.
| Depth | Area one cubic yard covers | Cubic yards per 100 sq ft |
|---|---|---|
| 1 in | 324 sq ft | 0.31 |
| 2 in | 162 sq ft | 0.62 |
| 3 in | 108 sq ft | 0.93 |
| 4 in | 81 sq ft | 1.23 |
| 6 in | 54 sq ft | 1.85 |
| 8 in | 40.5 sq ft | 2.47 |
| 12 in | 27 sq ft | 3.70 |
Compaction: why you order more than you measured
Dirt in a truck is loose, full of air gaps. When it is spread, tamped, watered and left to settle, those gaps close and the pile shrinks. How much depends on the soil and on how hard you pack it:
| How the fill will be treated | Allowance to add |
|---|---|
| Spread and raked, lightly walked on (beds, lawn top-ups) | about 10% |
| Typical fill, tamped by hand or settled with water | about 15–20% |
| Compacted in thin layers with a plate compactor or roller | about 20–30% |
The calculator starts at 15%. If you are filling a deep hole or building a pad that must not sink later, use 20% or more and compact in layers 4 to 6 inches thick.
Dirt weight and truck loads in brief
Delivered dirt weighs roughly 1 to 1.4 tons per cubic yard. The material list in the calculator uses these typical figures:
| Material | About lb per cubic yard | About tons per cubic yard |
|---|---|---|
| Fill dirt (typical, slightly damp) | 2,200 | 1.1 |
| Sandy fill | 2,500 | 1.25 |
| Clay fill | 2,600 | 1.3 |
| Sand (dry) | 2,700 | 1.35 |
| Wet fill dirt | 2,800 | 1.4 |
The dirt weight calculator converts between yards and tons, and the dump truck load calculator explains truck sizes. The load card always shows how much a full load of your material weighs, because a heavy load can max out a truck’s legal weight before its body is full.
Every figure here is an estimate for loose, delivered material. Soil weight changes a lot with moisture, so if your supplier quotes their own weight per yard or sells by the ton, use their numbers and check the order with them before the truck rolls.
Questions people ask
- How do I calculate how much dirt I need?
- Multiply length by width in feet to get square feet, multiply by the depth in feet (inches divided by 12) to get cubic feet, then divide by 27 to get cubic yards. Add 15 to 20 percent for compaction if the dirt will be packed down.
- How many square feet does a yard of dirt cover?
- One cubic yard covers about 324 square feet at 1 inch deep, 108 at 3 inches, 81 at 4 inches, 54 at 6 inches and 27 at 12 inches, before any allowance for compaction.
- How much does a cubic yard of dirt weigh?
- Roughly 2,000 to 2,800 pounds, or about 1 to 1.4 tons. Dry loose dirt sits near the bottom of that range; damp clay and wet fill sit at the top. Ask the supplier for their figure if you are ordering by the ton.
- Why add extra for compaction?
- Dirt is delivered loose. Once it is spread, tamped, watered and walked on, the air pockets close up and it takes up less room, often 15 to 20 percent less for typical fill and more if you compact it hard with a plate compactor.
- How many yards of dirt are in a dump truck?
- A single-axle dump truck usually carries about 5 to 7 cubic yards and a tandem-axle truck about 10 to 14. Heavy wet dirt can reach the truck's weight limit before the body is full, so ask the hauler what they can carry.