How to Calculate Cubic Feet (Definition and Examples)

By Indeed Editorial Team

Published May 29, 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Calculating cubic footage helps professionals, such as interior designers, landscapers, engineers, and construction contractors, determine how an object fits into a space. It often provides valuable insight into the area you may be working in, streamlining work processes, and improving team coordination. Understanding how to perform these calculations can benefit your career and improve your ability to complete personal tasks. In this article, we explore how to calculate cubic feet, examine three professions that use this calculation, and review the various measurement systems.

How to calculate cubic feet

Even though numerous online calculators are available to measure cubic footage, it can be both professionally and personally beneficial to understand how to calculate cubic feet by yourself. This ability allows you to define the total cubic feet of an item or equipment, and how much space you require to fit that object. Here are the steps to follow when learning how to calculate cubic feet:

1. Learn the formula

The formula for calculating cubic feet can make measuring a space easier. The calculation is straightforward and easy to do with a basic calculator. You can determine cubic feet with this formula:

Cubic feet = length x width x height

2. Convert measurements into feet

Sometimes the provided measurements of an object are shown in a different value, such as centimetres, inches, meters, or yards. This scenario is a common occurrence in certain professions dealing with companies, contractors, or clients that use the metric system. For example, suppose you're looking at a contractor's catalogue, and all its equipment is in centimetres. Knowing how to convert these values into feet can help avoid errors in your calculations, and determine what equipment is right for your designated space. Here are conversions to feet of the most prevalent units of length:

  • 1 meter (m) = 3.28 feet

  • 1 centimetre (cm) = 0.032 feet

  • 1 millimetre (mm) = 0.003 feet

  • 1 yard = 3 feet

  • 1 inch = 0.083 feet

3. Apply the cubic feet mathematical formula

Once all your measurements are in feet, you can use the mathematical formula to calculate the cubic footage of an object. Sometimes the object you want to measure is of an irregular shape. In those cases, the formula to calculate cubic footage is the same but requires dividing the item or equipment into sections. For example, suppose you have an L-shaped object. Here are the steps on how to perform that calculation in cubic feet:

  1. Divide the L-shaped object into two rectangle components.

  2. Find the length, width, and height of each rectangle, and ensure that all of your measurements are in feet.

  3. Use the mathematical formula to calculate the cubic footage of each rectangle by multiplying its length, width, and height.

  4. Add the two results of your calculations to discover the total cubic footage of the L-shaped object.

For example, suppose you have a piece of equipment that is 4 feet in length, 3.5 in width, and 1.20 in height. You can multiply these values, 4 (length) x 3.5 (width) x 1.20 (height) to find a total of 16.8. The final cubic footage of this piece of equipment is 16.8 feet.

Related: 21 Jobs in Architecture (With Salaries and Duties)

Three professions that use cubic feet calculations

Understanding how to calculate cubic feet can help you determine how much to include within a space, or whether an item you already have can fit in an area. This knowledge is vital for professionals in the field of construction, interior design, mathematics, engineering, carpentry, physics, and architecture. If you have an interest in pursuing a career in one of these fields, it can help your professional development to learn how each profession uses cubic footage calculations. Here are three career paths that often use cubic feet calculations with examples:

1. Interior designer

National average salary: $57,410 per year

Primary duties: Interior designers are creative professionals who oversee the design and decorative process for both working and living areas from start to finish. They visit job sites to analyze space availability, design the requirements and purpose of the space, attend client meetings to understand the design criteria and client preferences regarding interior styles and colours, and hire contractors and vendors to implement design ideas. Interior designers can also sketch plans either by hand or using computer-aided design software, which can help specify what materials and other items they require to complete a project.

For example, during house renovations, interior designers use cubic feet calculations to define the layout of the rooms within the constraints of the house while also mapping out the placement of essential living items, such as kitchen appliances, beds, dining tables, and sofas. They consider decorative items, like plants, paintings, and lamps, to fill rooms and add a certain feeling to them.

Related: How to Become an Interior Designer (With Salaries)

2. Construction manager

National average salary: $72,446 per year

Primary duties: Construction managers are responsible for overseeing the construction process for buildings and other pieces of infrastructure, like bridges and roads. They keep daily employee logs, monitor employee conduct, establish risk factors, and then manage and mitigate them to ensure smooth construction. Construction managers can also conduct in-depth project analyses to develop the budget and deliverables.

For example, construction managers work closely with architects and engineers to establish the requirements for constructing an apartment building. One of those requirements is performing cubic feet calculations to determine essential factors, such as the size of the plot of land, how far to dig into the ground to build the foundation, and the amount of material they require to begin construction. These calculations can also inform them of how many operators and labourers they require, and estimate how long the entire construction process may take.

Related: How to Become a Construction Manager in 7 Steps

3. Plant operator

National average salary: $24.60 per hour

Primary duties: Plant operators are responsible for maintaining daily processes, monitoring work progress, and using various pieces of specialized equipment. They often conduct periodic inspections to ensure proper maintenance of machinery and safe working conditions. Operators usually enforce the plant's safety regulations and policies and perform basic troubleshooting and operational analysis to provide corrective measures when required.

For example, power stations use natural gas to generate electricity, and power plant operators can measure natural gas by volume in cubic feet. A cubic foot of gas is the amount of gas required to fill a volume of one cubic foot under set temperature and pressure conditions. To achieve more accurate measurements of fuel and energy, operators typically convert cubic feet to British thermal units (BTUs) in their calculations instead of using the formula that accounts for length, width, and height. As a reference, one cubic foot equals 1,000 BTUs.

Related: 13 Best Paying Jobs in Energy (And How to Find One)

The different measurement systems for cubic feet calculation

The various measurement systems represent complementary knowledge that can help you perform more accurate calculations of cubic footage. Each system accounts for different units of length and their application often depends on the company's country of origin. Understanding these measurement systems can prepare you for job interview questions and ease your work processes. Here are the two most common measurement systems:

The international system of units

Most countries use the international system of units (SI), which is a modern representation of the metric system, as their primary measurement system. The wide adoption of SI results from a desire to standardize measurements globally, aiming to improve international collaboration between companies and reduce mathematical discrepancies.

For example, suppose you work in a manufacturing facility and order an item from a client that uses SI metrics to measure equipment. Knowledge of SI can help you conduct the appropriate conversions to calculate cubic feet, ensuring an accurate measurement of a designated area. SI features seven base units:

  • Second (s) to measure time

  • Metre (m) to measure length

  • Kilogram (kg) to measure mass

  • Ampere (A) to measure electric current

  • Kelvin (K) to measure thermodynamic temperature

  • Mole (mol) to measure the amount of substance

  • Candela (cd) to measure luminous intensity

The US customary system

The United States uses the US customary system as its official measurement system. It's most present in its national commercial activities, road signs, cooking recipes, and weather reports. For example, suppose you're a construction worker and your task is to install two soccer nets in a school's soccer field surrounded by a track and field path. The schematics for the soccer field feature yard dimensions. You can perform a conversion from yards to feet to calculate the cubic footage of the field and ensure the soccer nets fit appropriately within the available space.

The US customary system includes the following units of measurement:

  • Length features feet (ft), inches (in), yards (yd), and miles (mi)

  • Weight features ounce (oz), pound (lb), and ton (T)

  • Temperature features Fahrenheit (°F)

  • Capacity features teaspoons (t), tablespoons (T), cups (C), pints (pt), quarts (qt), gallons (gal), and fluid ounces (fl oz)

  • Area features square units for inches, feet, yards, acres, and miles

  • Volume features cubic units for inches, feet, and yards

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