This cubic feet calculator helps you find the volume of any rectangular space quickly and accurately, no matter what units you're starting with. Whether you're measuring a room in feet, sizing a shipping box in inches, or working with metric measurements in centimeters, this tool handles the conversions and math for you.
If you've ever stood in front of a storage unit wondering whether your furniture will fit, tried to figure out how many bags of mulch to buy for a garden bed, or needed to estimate freight volume for a shipment, you know how useful a reliable volume calculation can be. Just enter your length, width, and height in whatever units you have, and you'll get your volume in cubic feet — plus the option to convert to liters, gallons, cubic meters, and more.
What Are Cubic Feet?
A cubic foot is a unit of volume that represents the space inside a cube measuring one foot on each side. Think of it as a box that's 12 inches long, 12 inches wide, and 12 inches tall. That single box holds about 7.48 gallons of water, which gives you a practical sense of the size.
Cubic feet are the standard volume measurement across many industries in the United States. You'll see them used for:
- Moving and storage — truck capacities and storage units are listed in cubic feet
- Appliances — refrigerators, freezers, and microwaves are rated by cubic feet of interior space
- HVAC systems — airflow is measured in cubic feet per minute (CFM)
- Shipping and freight — cargo volume determines pricing
- Landscaping — soil, mulch, gravel, and concrete quantities
Understanding cubic feet gives you a common language for comparing spaces, containers, and material quantities — even when original measurements come in different units.
How to Calculate Cubic Feet
The basic formula is straightforward:
Volume (ft³) = Length (ft) × Width (ft) × Height (ft)
If your measurements are already in feet, multiply the three numbers together and you're done. A closet that's 6 feet long, 3 feet wide, and 8 feet tall has a volume of 144 cubic feet (6 × 3 × 8 = 144).
When Your Measurements Are in Other Units
Most of the time, your measurements won't all be in feet. Here's how to handle the most common conversions:
From inches: Divide each measurement by 12 to convert to feet, then multiply.
Volume (ft³) = (Length in inches ÷ 12) × (Width in inches ÷ 12) × (Height in inches ÷ 12)
Or take a shortcut: multiply all three inch measurements together, then divide by 1,728 (which is 12 × 12 × 12).
From centimeters: Divide each measurement by 30.48 to convert to feet.
From meters: Multiply each measurement by 3.281 to convert to feet.
From yards: Multiply each measurement by 3 to convert to feet.
You don't need to memorize these — this calculator handles any combination of units automatically. But knowing the underlying math can be helpful when you're doing quick estimates on the fly.
How to Use This Calculator
- Enter your length — Type the length measurement into the first field and select the matching unit from the dropdown (feet, inches, centimeters, meters, yards, or others).
- Enter your width — Type the width measurement and select its unit. It doesn't need to match the length unit — you can mix inches and feet, or centimeters and meters, and the calculator sorts it out.
- Enter your height — Type the height (or depth, depending on what you're measuring) and choose the unit.
- Read your result in cubic feet — The calculator instantly displays the volume in cubic feet (ft³).
- Convert to other units — Use the "Volume in other units" dropdown to see your result in cubic meters, liters, gallons, cups, or any other volume unit you need.
That's it. No need to convert everything to the same unit first — the calculator does that work behind the scenes.
Common Conversions Reference
These are the volume conversions you're most likely to need:
From Cubic Feet | To | Multiply By |
|---|---|---|
1 ft³ | Cubic inches | 1,728 |
1 ft³ | Cubic meters | 0.0283 |
1 ft³ | Cubic yards | 0.0370 |
1 ft³ | Liters | 28.317 |
1 ft³ | US Gallons | 7.481 |
1 ft³ | UK Gallons | 6.229 |
1 ft³ | US Fluid Ounces | 957.5 |
1 ft³ | Cups | 119.7 |
A few quick reference points that are handy to remember: one cubic foot holds roughly 7.5 gallons, about 28.3 liters, and equals 1,728 cubic inches. Those three conversions cover the majority of everyday situations.
Practical Examples
Moving and Storage
You're renting a storage unit that's 10 feet long, 10 feet wide, and 8 feet tall. That gives you 800 cubic feet (10 × 10 × 8). A typical moving truck holds between 400 and 800 cubic feet, so this unit has roughly the same capacity as a full-size moving truck.
Garden Soil
Your raised garden bed measures 4 feet long, 3 feet wide, and 10 inches deep. Since the depth is in inches, convert it: 10 ÷ 12 = 0.833 feet. The volume is 4 × 3 × 0.833 = 10 cubic feet. Bags of garden soil typically come in 1 or 2 cubic foot bags, so you'd need about 10 one-cubic-foot bags or 5 two-cubic-foot bags.
Shipping a Package
You're shipping a box that measures 24 inches × 18 inches × 16 inches. In cubic inches, that's 24 × 18 × 16 = 6,912 cubic inches. Divide by 1,728 to get cubic feet: 6,912 ÷ 1,728 = 4 cubic feet. Many freight carriers use cubic feet to calculate dimensional weight and pricing, so knowing this number helps you estimate shipping costs upfront.
Concrete for a Patio Slab
You're pouring a concrete slab that's 12 feet long, 10 feet wide, and 4 inches thick. Convert the thickness: 4 ÷ 12 = 0.333 feet. Volume = 12 × 10 × 0.333 = 40 cubic feet. Since concrete is usually sold by the cubic yard, divide by 27: 40 ÷ 27 = 1.48 cubic yards. You'd want to order about 1.5 cubic yards to account for slight variations and waste.
Refrigerator Capacity
A refrigerator's interior measures 28 inches wide, 30 inches deep, and 60 inches tall. That's 28 × 30 × 60 = 50,400 cubic inches, or 50,400 ÷ 1,728 = 29.2 cubic feet. This interior measurement helps you compare fridge capacities regardless of the external dimensions.
Tips for Accurate Measurements
Getting a good volume calculation starts with getting good measurements. A few practical pointers:
- Measure the inside dimensions if you're trying to figure out how much something can hold (like a planter or a storage container). Measure the outside dimensions if you're trying to figure out how much space something takes up.
- Account for irregular shapes by breaking them into smaller rectangular sections. Calculate the cubic feet for each section separately, then add them together.
- Round up for materials like soil, mulch, gravel, and concrete. It's always better to have a little extra than to come up short mid-project. A good rule of thumb is to add 5-10% to your calculated volume.
- Double-check your units before entering them. The most common calculation mistakes come from mixing up inches and feet, or forgetting to convert one measurement while the others are already in the right unit.
- For appliances and furniture, check the manufacturer's spec sheet first. They usually list dimensions more precisely than you can measure with a tape measure, especially for curved or angled items.