How to use the dirt calculator
- Choose the shape. Rectangle, circle, several parts for L-shapes and curves, or type in the area if you already know it.
- Enter the size and depth. Length and width in feet; depth in inches. Feet and inches like 12' 6" work too.
- Read the result in cubic yards, tons and bags. Under Adjust assumptions you can change the weight per yard, extra and bag size.
- Add your supplier's price per ton, yard or bag to see the cost, including delivery.
The fill dirt formula
Cubic feet = area (sq ft) × depth (in) ÷ 12
Cubic yards = cubic feet × (1 + extra) ÷ 27
Tons = cubic yards × weight per cubic yard
Bags = cubic feet with extra ÷ bag size, rounded up
Worked example
Raising a 20 × 10 ft area by 6 inches
- 200 sq ft × 0.5 ft = 100 cu ft; with 5% = 105 cu ft.
- 105 ÷ 27 = 3.89 cubic yards.
- At about 1.2 tons per yard: 4.67 tons. Compacted fill can need 20% more.
How far a cubic yard goes
| Depth | One cubic yard covers | 1 cu ft bags per 10 sq ft |
|---|---|---|
| 1 in | 324 sq ft | 0.8 |
| 2 in | 162 sq ft | 1.7 |
| 3 in | 108 sq ft | 2.5 |
| 4 in | 81 sq ft | 3.3 |
| 6 in | 54 sq ft | 5.0 |
A cubic yard is 27 cubic feet, or 27 bags of 1 cu ft.
Filling and leveling tips
- Spread fill in layers of about 4 to 6 inches and compact each one.
- Finish with 4 to 6 inches of topsoil if you want grass to grow.
- Aim for a slope of about 6 inches over the first 10 feet away from the house.
Common mistakes to avoid
- Ignoring compaction. Compacted fill takes noticeably more dirt than loose measurements suggest.
- Fill against the house. Ground must slope away from the foundation; never bury siding or vents.
- Raising soil around trees. Even a few inches of fill over roots can kill a tree.
- No 811 call. Call before digging to fill or regrade.
Frequently asked questions
How do I calculate how much dirt I need?
Multiply length × width × depth, all in feet, and divide by 27 for cubic yards. A 20 × 10 ft area raised 6 in needs 20 × 10 × 0.5 = 100 cu ft, or 3.7 cubic yards before any extra.
What is the difference between fill dirt and topsoil?
Fill dirt is subsoil with few organics, used to raise and level ground because it compacts and stays put. Topsoil is the richer upper layer for growing grass and plants. Use fill underneath and finish with a few inches of topsoil.
How much extra fill do I need for compaction?
Loose fill compacts by roughly 10 to 25% when it is tamped or rolled. If you will compact the dirt, set the extra to 20% or more under Adjust assumptions.
How much does a yard of dirt weigh?
About 1.1 to 1.4 tons. Clay-heavy and wet dirt is at the top of that range. Check whether your truck or trailer can carry it.
How much dirt does a dump truck hold?
A small dump truck often carries 5 to 10 cubic yards, a tandem 10 to 16. Ask the supplier; weight limits can cap the load before volume does.