Omni Cubic Yard Calculator: How It Works

This calculator works out the volume in cubic yards from the length, width, and depth (or height) you enter, and it also converts the result to cubic feet and cubic meters. You type in the three dimensions in feet and inches (or meters and centimeters), pick the shape you are measuring, and get the cubic yardage plus the equivalent in other units. The result tells you how much material, such as soil, gravel, or concrete, would fill that space.

Formula

The basic formula for a rectangular space is:

Volume (cubic yards) = Length × Width × Depth ÷ 27

Where:

• Length is the longest side of the area, in feet.
• Width is the shorter side, in feet.
• Depth is how deep the material goes, in feet (if you enter inches, divide by 12 first).
• 27 is the number of cubic feet in one cubic yard (3 feet × 3 feet × 3 feet).

If you are measuring a circular area, the formula becomes:

Volume = π × (radius in feet)² × Depth in feet ÷ 27

For a triangular area, use:

Volume = (base × height ÷ 2) × Depth ÷ 27

Worked Example

Using the default values from the calculator above:

• Length = 10 feet
• Width = 5 feet
• Depth = 4 inches

First convert depth to feet: 4 inches ÷ 12 = 0.3333 feet.

Then multiply: 10 × 5 × 0.3333 = 16.6665 cubic feet.

Finally divide by 27: 16.6665 ÷ 27 = 0.6173 cubic yards.

The calculator rounds to two decimals and shows 0.62 cubic yards.

Why You Need Cubic Yards

Landscaping and construction materials are usually sold by the cubic yard. Topsoil, mulch, gravel, sand, and concrete are all priced per cubic yard, so knowing the volume before you order prevents two common problems:

• Ordering too little – you run out mid-project and have to pay for a second delivery.
• Ordering too much – you are left with a pile of material you cannot return.

For example, a 10×10-foot garden bed that needs 6 inches of new soil requires 10 × 10 × 0.5 = 50 cubic feet, which is 50 ÷ 27 = 1.85 cubic yards. Most suppliers will sell you 2 cubic yards, and you will have a little extra for settling.

How to Measure Correctly

Accurate measurements are the difference between a good estimate and a wasted trip to the store. Follow these steps:

1. Use the same unit for all dimensions. If you measure length in feet, measure width in feet and depth in feet. Convert inches to feet by dividing by 12.
2. Measure the actual opening, not the outer edges. For a raised bed, measure the inside dimensions. For a hole, measure the top opening and the bottom if it is not a perfect rectangle.
3. For irregular shapes, break the area into rectangles. Calculate each rectangle separately, then add the cubic yards together.
4. For circular areas, measure the diameter (straight across the center) and divide by 2 to get the radius. Then use the circle formula.
5. Add a small buffer for settling. Loose materials like soil and mulch compress after rain or foot traffic. Adding 5–10% to your final volume is a common practice.

Common Mistakes and How to Avoid Them

The most frequent error is mixing units. A depth of 4 inches is not 4 feet. If you plug 4 into a formula that expects feet, you get 27 times too much volume. Always convert inches to feet first.

Another mistake is forgetting that a cubic yard is a three-dimensional measure. A square yard is 3 feet by 3 feet, but a cubic yard is 3 feet by 3 feet by 3 feet – that is 27 cubic feet, not 9.

Also, be careful with the difference between cubic yards and yards. A yard is a length; a cubic yard is a volume. They are not interchangeable.

Finally, when measuring a sloped area, the depth should be measured perpendicular to the surface, not along the slope. For example, if you are filling a sloped trench, measure the vertical depth, not the length of the slope.

Comparing Cubic Yards to Other Units

If you are used to metric measurements, here is how cubic yards compare:

• 1 cubic yard = 27 cubic feet
• 1 cubic yard ≈ 0.7646 cubic meters
• 1 cubic yard ≈ 764.6 liters
• 1 cubic meter ≈ 1.308 cubic yards

Most online calculators and suppliers will let you switch between units, but it is helpful to know the conversion factors so you can sanity-check a quote. For instance, if a supplier quotes you 2 cubic meters, that is about 2.6 cubic yards – a significant difference if you are ordering by the yard.

Limitations of the Calculator

This calculator assumes a perfectly rectangular or circular shape with a uniform depth. Real-world projects often have variations:

• Soil settles after being dumped, so the final surface may be lower than you measured.
• Rock or gravel may have gaps that make the actual volume needed different from the calculated volume.
• For very large areas, the curvature of the ground can affect the volume.

For most home projects, the calculator gives a close estimate, but it is always wise to order a little extra (5–10%) for settling and compaction. For critical structural fills, consult a professional who can perform a site survey.

Frequently Asked Questions

How many cubic feet are in a cubic yard?

There are 27 cubic feet in one cubic yard. This comes from 3 feet × 3 feet × 3 feet. To convert cubic feet to cubic yards, divide by 27.

How do I calculate cubic yards for a circular area?

Measure the diameter in feet, divide by 2 to get the radius, then use the formula: π × radius² × depth (in feet) ÷ 27. For example, a circular garden with a 10-foot diameter and 6-inch depth is π × 5² × 0.5 ÷ 27 ≈ 1.45 cubic yards.

What if my depth is in inches?

Convert inches to feet by dividing by 12. For example, 6 inches becomes 0.5 feet, and 4 inches becomes 0.333 feet. Then use the formula as usual.

How much does a cubic yard of topsoil weigh?

Topsoil typically weighs between 1,500 and 2,000 pounds per cubic yard, depending on moisture content. Dry topsoil is lighter, while wet topsoil can be much heavier. This calculator only gives volume, not weight.

Do I need to add extra for settling?

Yes, it is common to add 5–10% to the calculated volume for loose materials like soil, mulch, or sand. These materials compact over time, so a little extra ensures you do not run short.

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in l | Length | ft | 10 | 0
in w | Width | ft | 5 | 0
in d | Depth | in | 4 | 0
out yards | Cubic yards | yd³ | (l * w * (d / 12)) / 27 | 2
out cubic_ft | Cubic feet | ft³ | l * w * (d / 12) | 2
out cubic_m | Cubic meters | m³ | (l * w * (d / 12)) * 0.0283168 | 2