What this calculator does
Find out how much soil a hole or trench will remove, and how many truckloads it takes to haul away. Soil takes up more room once it's dug. In the ground, it's packed tight. In the bucket and the truck, it's broken up, with air between the clumps. So a hole of 10 cubic yards fills well over 10 cubic yards of truck. Diggers call the volume in the ground the bank volume. The dug-up volume is the loose volume, and the growth between them is the swell.
The calculator works for a rectangular dig (a trench, footing or pad) or a round one (a hole, pier or pond). It finds the bank volume from the size and depth, times the number of identical digs. It gives the answer in cubic yards and cubic meters. Then it adds the swell to get the loose volume. Finally, it divides by your truck's capacity to count the loads to haul.
Where it's used
Why this math matters outside the classroom:
- Footing digs. Builders digging a 20 × 15 ft pad 3 ft deep remove 900 ft³, which is 900 ÷ 27 = 33.3 cubic yards.
- Post holes. Fence installers digging 12 holes 1 ft across and 3 ft deep remove 12 × π × 0.5² × 3 ≈ 28.3 ft³ of soil.
- Hauling quotes. Contractors turn 33.3 bank yards into 41.7 loose yards at 25% swell and book five 10-yard trucks.
- Garden ponds. Homeowners digging a 10 ft round pond 3 ft deep find π × 5² × 3 ≈ 236 ft³ to move.
- Cylinder volume. Students compare a 1 ft wide, 3 ft deep post hole (2.36 ft³) with a 1 ft square hole of the same depth (3 ft³).
Grade level and standards: Grades 7–8; Common Core State Standards for Mathematics 7.G.B.6, 8.G.C.9. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Choose a rectangular or round dig and enter its length and width, or its diameter.
- Enter the depth in feet and the number of identical digs.
- Set a swell factor for your soil and the capacity of the truck in loose cubic yards.
- Read the bank volume, loose volume and truckloads.
What the inputs mean
- Depth
- For inches, divide by 12: 6 in = 0.5 ft, 18 in = 1.5 ft.
- Number of identical digs
- Use this for repeated digs of the same size, such as post holes, pier footings or planting holes.
- Swell (bulking) factor
- Swell depends on the material and how wet it is. Clean sand and gravel bulk up by roughly 10 to 15%. Ordinary soil and loam grow by about 20 to 30%. Clay and broken rock grow by 30% or much more. Your excavator or a geotechnical report (a soil study by an engineer) can give a better figure.
- Truck capacity
- Trucks are limited by both volume and weight. A load of wet clay can hit the weight limit before the bed is full. Ask the hauler how much of your material they'll carry.
Formula and method
rectangular: volume (ft³) = length × width × depth × count round: volume (ft³) = π × (diameter ÷ 2)² × depth × count bank volume (yd³) = ft³ ÷ 27 loose volume = bank volume × (1 + swell ÷ 100) truckloads = loose volume ÷ truck capacity, rounded up
A dig with straight-down sides is a box or a cylinder (a round can shape). So its volume is its floor area times its depth. π (pi) is about 3.1416, and the small ² means a number times itself. Count is the number of identical digs. One cubic yard is 3 × 3 × 3 = 27 cubic feet.
Swell is the percentage the soil grows once it's dug. It's added to the bank volume, because hauling and dumping are priced on what fills the truck. Truckloads round up, because a part load is still a trip.
Worked example
A 20 × 15 ft pad dug 3 ft deep in ordinary soil with 25% swell, hauled in 10 yd³ trucks.
- Volume: 20 × 15 × 3 = 900 ft³.
- Bank volume: 900 ÷ 27 = 33.3333 yd³.
- Loose volume: 33.3333 × 1.25 = 41.6667 yd³.
- Truckloads: 41.6667 ÷ 10 = 4.1667, rounded up to 5.
Result: The dig removes about 33.33 yd³ of soil in place, which becomes about 41.67 yd³ once loosened, or five 10 yd³ truckloads.
Understanding the result
Use the bank volume to compare with the plans and to price the digging. Use the loose volume and truckloads to book hauling and disposal.
Soil put back as fill and packed down ends up smaller than its loose volume. It's often smaller than its bank volume too. So you can't use the same swell figure to plan backfill.
Assumptions and limitations
- The sides of the dig go straight down, and the bottom is level.
- The swell factor is the same for all the soil removed.
- Safety rules often require sloped or stepped (benched) sides for deeper trenches. Those sides remove more soil than straight ones. Work them out separately.
- Uneven ground needs an average depth or a survey.
- Weight limits on trucks aren't checked. Before digging, contact your local utility locating service.
Frequently asked questions
What is the difference between bank and loose cubic yards?
Bank cubic yards measure soil in the ground, undisturbed. Loose cubic yards measure the same soil after digging, when it has bulked up. Compacted cubic yards measure it again after it's put back and packed down as fill.
What swell factor should I use?
For a rough plan, about 25% suits ordinary soil, 10 to 15% suits sand or gravel, and 30 to 40% suits clay. Rock that's broken out can swell 50% or more. Local experience with your soil is the best guide.
How many truckloads is a cubic yard of dirt?
One bank cubic yard is about 1.25 loose cubic yards of ordinary soil. So a 10 yd³ truck carries about 8 bank cubic yards per load, if weight allows.
How do I measure depth in inches?
Divide inches by 12 to get feet: 6 in is 0.5 ft, 9 in is 0.75 ft and 18 in is 1.5 ft.
How this calculator is checked
Method: Prism and cylinder volumes; 27 ft³ per yd³ and 0.764554857984 m³ per yd³ (exact); loose volume from a user-entered swell percentage; whole-truck rounding. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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