Excavation Calculator Cubic Yard
Our Excavation Calculator helps you work out the estimated volume from your project’s dimensions. You can use the result to understand how many cubic yards of earth your project involves and prepare a basic excavation budget.
You do not need advanced construction knowledge to use the calculation. You only need the size of the area you plan to dig. The important part is knowing which measurements to enter and what the final number actually tells you.
Start With the Size of Your Excavation
Imagine you are preparing a site for a detached garage. The ground needs to be lowered before the next stage of construction can begin. Your contractor asks for the length, width, and planned digging depth.
These three measurements determine the volume of a simple, box-shaped excavation.
The length runs from one end of the area to the other. The width measures across it, while the depth tells you how far down the ground will be removed.
For a rectangular excavation, the calculation is:
Volume = Length × Width × Depth
All measurements must use the same unit. If you measure the length in feet, the width and depth should also be in feet.
Suppose your garage excavation measures 26 feet long, 20 feet wide, and 3 feet deep.
26 × 20 × 3 = 1,560 cubic feet
The answer is 1,560 cubic feet. However, excavation contractors and hauling services may discuss larger quantities in cubic yards. You can convert the result by dividing it by 27.
1,560 ÷ 27 = 57.78 cubic yards
You would therefore have an estimated excavation volume of 57.78 cubic yards for that rectangular space.
This is the volume of the space being dug, not necessarily the exact volume of loose dirt that will be loaded into trucks.
Calculate Cubic Yards Without Confusing the Units
Cubic yards are useful when estimating bulk material quantities and excavation work in the United States. One cubic yard contains 27 cubic feet.
That relationship gives you two simple calculations:
To convert cubic feet into cubic yards, divide by 27.
To convert cubic yards into cubic feet, multiply by 27.
For example, if your excavation measures 2,430 cubic feet, divide that figure by 27.
2,430 ÷ 27 = 90 cubic yards
If a contractor estimates that the job involves 90 cubic yards of in-ground material, you can use that figure as a starting point when discussing the scope of work.
What if the depth is measured in inches?
You must convert the depth before using the formula if the other dimensions are in feet.
Suppose you need to remove soil from an area measuring 18 feet by 14 feet, with a depth of 15 inches.
First, convert inches to feet:
15 ÷ 12 = 1.25 feet
Now calculate the volume:
18 × 14 × 1.25 = 315 cubic feet
Convert the answer to cubic yards:
315 ÷ 27 = 11.67 cubic yards
The estimated volume is 11.67 cubic yards.
If you skip the unit conversion and enter 15 as though it were feet, the result will be much too large. Always check the measurement units before calculating.
A Few Volumes Worth Knowing
| Volume in cubic feet | Equivalent cubic yards |
|---|---|
|
27 |
1 |
|
81 |
3 |
|
135 |
5 |
|
270 |
10 |
|
540 |
20 |
These are direct conversions, not recommended quantities for any particular project. Your own result will depend on the dimensions of the area being excavated.
If you need to calculate other construction volumes, visit our Cubic Yard Calculator for help with cubic-yard measurements.
What Will Your Excavation Actually Cost?
Knowing the volume is only the first part of planning. The next question is how much the digging will cost.
There is no single price that applies to every excavation job. Some contractors charge by the hour, while others quote a fixed amount for the project or use a price per cubic yard. The rate can also depend on the type of ground, the machinery required, and whether the excavated soil needs to be hauled away.
When you have a rate per cubic yard, the calculation is simple:
Estimated cost = Excavation volume × Price per cubic yard
Consider a project with an estimated volume of 60 cubic yards. For illustration, suppose the quoted rate is $30 per cubic yard.
60 × $30 = $1,800
The calculated amount is $1,800.
This example assumes that the $30 rate applies to the entire volume. It does not establish the going market rate, and it should not be treated as a complete quote unless the contractor confirms what is included.
Compare Different Rates for the Same Job
A change in the quoted rate can make a substantial difference to the budget. Here is how different hypothetical rates would affect a 60-cubic-yard excavation.
| Assumed rate per cubic yard | Calculated amount |
|---|---|
|
$20 |
$1,200 |
|
$25 |
$1,500 |
|
$30 |
$1,800 |
|
$40 |
$2,400 |
|
$50 |
$3,000 |
Use actual quotes when planning your budget. A contractor’s rate may include digging only, or it may cover several services together.
Before agreeing to a price, ask whether it includes machine operation, labor, loading, transportation, disposal fees, and site preparation. If these items are charged separately, add them to your budget rather than assuming they are covered by the excavation rate.
Basement Excavation Needs Extra Planning
Digging a basement is different from removing a shallow layer of soil from a garden. The excavation is deeper, the amount of material can be substantial, and the work may require careful planning around nearby structures and underground conditions.
For an initial volume estimate, consider a rectangular basement excavation measuring 36 feet long, 30 feet wide, and 8 feet deep.
First, multiply the dimensions:
36 × 30 × 8 = 8,640 cubic feet
Then convert to cubic yards:
8,640 ÷ 27 = 320 cubic yards
The calculated volume is 320 cubic yards.
Now imagine that a contractor provides a hypothetical rate of $35 per cubic yard for the work covered by that rate.
320 × $35 = $11,200
The result is $11,200 before any additional charges that may apply. This is a worked example, not a verified basement excavation price.
The actual excavation area may be larger than the basement’s finished dimensions. Contractors may need additional working room, and the excavation plan may include sloped sides, footing areas, or other features. Groundwater, rock, soil stability, and access for machinery can also affect the method and price.
For this reason, use a basement excavation calculation for preliminary planning. Confirm the required dimensions and full scope of work with the contractor before setting a final budget.
Work Out the Volume of a Trench
A trench may be needed for drainage pipes, water lines, electrical conduits, or other underground services. Although the shape is different from a basement, the basic calculation is the same when the trench has a uniform rectangular cross-section.
For example, imagine a trench that is 120 feet long, 2 feet wide, and 2.5 feet deep.
120 × 2 × 2.5 = 600 cubic feet
600 ÷ 27 = 22.22 cubic yards
The estimated trench volume is 22.22 cubic yards.
This approach works best when the trench maintains the same width and depth throughout its length. If the ground slopes or the trench changes dimensions, split it into smaller sections and calculate each one separately. Add the section volumes to estimate the total.
Utility trenches also require care beyond the volume calculation. In the United States, contact 811 before digging so underground utility lines can be marked through the applicable local process. Follow the project plans and relevant safety requirements for the trench.
Pool and Yard Excavation: Do the Shapes Matter?
Yes. The shape of the area can change how you calculate the volume.
A rectangular pool excavation may be estimated using length, width, and average depth. A pool with a sloping bottom, however, does not have one uniform depth. Using only its deepest point may overstate the volume, while using only its shallowest point may understate it.
For an initial estimate, you can use an appropriate average depth or divide the pool into sections. The pool installer should confirm the excavation dimensions, including any additional space required for construction.
Landscaping projects can have similar challenges. Perhaps you are lowering a lawn, preparing a patio, or removing soil to level a section of your yard. If the ground is reasonably even, a rectangular calculation may be sufficient. When the elevation changes across the site, smaller sections usually give a more useful estimate.
For instance, calculate each section’s volume using its own dimensions and average depth. Then add the results together.
If the project involves bringing in replacement soil, remember that the quantity required to fill an area is a separate calculation from the quantity removed. Our Cubic Yard Calculator can help with general volume calculations, while a Topsoil Calculator can be linked here once the dedicated page is available.
The Dirt May Take Up More Space After Digging
One detail often missed in excavation planning is the difference between soil in the ground and soil after it has been removed.
Undisturbed soil is packed together in its natural position. Digging breaks up that material and creates additional spaces between particles. As a result, the loose soil may occupy more space than it did before excavation.
Construction professionals commonly distinguish between three volume states:
Bank volume: The material measured in its original, undisturbed condition.
Loose volume: The material after excavation, when it has been broken up and moved.
Compacted volume: The material after it has been placed and compacted.
These quantities are related, but they are not interchangeable.
For example, a calculation showing 20 cubic yards of excavation describes the volume of the space being dug. It does not guarantee that the resulting loose soil will fit into a truck with exactly 20 cubic yards of capacity.
The difference depends on the soil type, moisture, compaction, and excavation method. Avoid applying the same expansion percentage to every job. If you are arranging transport, ask the contractor or hauling company to estimate the loose volume and the number of loads required.
Why the Calculated Amount May Differ From the Final Job
Even careful measurements cannot account for every condition beneath the surface. Several things can change the amount of work involved.
Ground conditions: Dense clay, buried debris, and rock may require different equipment or methods from ordinary soil.
Water in the ground: Groundwater or waterlogged soil can affect the excavation process and may require pumping or drainage measures.
Limited working space: A narrow entrance or nearby building can restrict the size of the equipment that can reach the site.
Extra excavation space: A foundation or pool may require digging beyond the dimensions of the finished structure.
Removal and disposal: The excavated material may need to be transported to a suitable location. The associated charges depend on the material, distance, and disposal arrangements.
Uneven ground: A single set of dimensions may not accurately represent an area with changing elevations or depth.
These factors do not make an excavation calculator less useful. They explain why its result should be treated as a planning estimate rather than a substitute for a site assessment.
Before You Start Digging
Take a few minutes to check the project details before arranging excavation work.
Confirm the planned length, width, and depth.
Make sure all measurements use consistent units.
Check the excavation limits against the project drawings.
Identify underground utilities before digging.
Ask whether the contractor’s quote includes hauling and disposal.
Discuss rock, groundwater, restricted access, and other known site conditions.
Confirm any applicable permits and safety requirements.
For deep or complex excavations, do not rely on a volume calculation alone to determine how the site should be dug. Follow the project design and obtain qualified advice where required.
Frequently Asked Questions
How do I calculate excavation volume in cubic yards?
Multiply the length, width, and depth in feet. Divide the answer by 27 to convert cubic feet into cubic yards.
For example, an area measuring 20 feet long, 10 feet wide, and 3 feet deep has a volume of 600 cubic feet, or approximately 22.22 cubic yards.
Can an excavation calculator estimate the cost?
Yes, if you enter a suitable price per cubic yard. Multiply the estimated volume by the quoted rate. Add separate charges for labor, machinery, hauling, disposal, or other services if they are not included.
How do I estimate basement excavation?
Multiply the excavation length by its width and depth, then divide by 27 if the measurements are in feet. This gives the volume in cubic yards. The final price depends on the actual excavation plan, ground conditions, access, and the services included in the contractor’s quote.
What is the difference between excavation volume and loose soil volume?
Excavation volume describes the space removed from the ground. Loose soil volume describes the material after digging. Because disturbed soil may expand, the loose volume can be larger than the original in-ground volume.
Can I use this method for a swimming pool?
Yes, for a rectangular excavation with a uniform depth. For a sloping pool floor or an irregular design, use an appropriate average depth or calculate separate sections. Confirm the dimensions with the pool installer.
Why should I convert inches into feet?
The standard formula produces cubic feet when length, width, and depth are all in feet. If one measurement remains in inches, the calculation will be incorrect. Divide the number of inches by 12 to convert it to feet.
Does the calculator include the cost of removing soil?
Not unless the tool specifically includes hauling and disposal costs. The volume calculation estimates the amount of space being excavated. Transport and disposal should be checked separately when preparing a budget.
Make Your Excavation Estimate Before Work Begins
Knowing the approximate excavation volume gives you a clearer starting point for planning a construction or landscaping project. You can compare dimensions, convert the result to cubic yards, and calculate a preliminary cost when you have a suitable rate.
Start with accurate measurements and account for differences in depth or shape. Then confirm the excavation plan and any extra charges with your contractor. That approach will give you a more useful estimate than relying on a rough guess.