Multiply the number of feet by 12 to get inches
To change feet to inches, multiply the number of feet by 12. Since one foot equals 12 inches, this is the only step you need. For example, 5 feet equals 5 × 12 = 60 inches. You can use this method for any measurement, whether it is a fraction of a foot or a much larger distance.
The number 12 is the conversion factor because the imperial measurement system defines a foot as exactly 12 inches. This relationship never changes, so the multiplication method works the same way every time. Once you know that one foot = 12 inches, you can convert any number of feet into inches by multiplying.
Key Takeaways
- One foot always equals 12 inches, so multiply feet by 12 to convert to inches.
- If you have both feet and inches (like 5 feet 8 inches), multiply only the feet by 12, then add the remaining inches.
- To reverse the process and change inches back to feet, divide the number of inches by 12.
- This conversion works the same way whether you are measuring height, distance, length, or any other dimension.
- Decimal feet (like 3.5 feet) convert the same way — multiply by 12 to get the total inches.
Working with measurements that include both feet and inches
When you have a measurement like 6 feet 3 inches, convert only the feet portion. Multiply 6 by 12 to get 72 inches, then add the 3 remaining inches for a total of 75 inches. This two-step process keeps you from losing the inches that are already part of your measurement.
The same approach works in reverse. If someone tells you a measurement is 90 inches and you want to express it in feet and inches, divide 90 by 12. You get 7 with a remainder of 6, which means 7 feet 6 inches. The whole number from the division becomes your feet, and the remainder becomes your inches.
Using a straightforward table for quick reference
A conversion table can help you check your work or find common conversions without doing the math each time. The table below shows how many inches equal common foot measurements:
| Feet | Inches |
|---|---|
| 1 | 12 |
| 2 | 24 |
| 3 | 36 |
| 4 | 48 |
| 5 | 60 |
| 6 | 72 |
| 7 | 84 |
| 8 | 96 |
| 10 | 120 |
For any measurement not shown in the table, the multiplication method works just as well. You can also use the table to verify your answer after you multiply, which is a useful way to catch mistakes before you use the measurement for something important.
Converting decimal feet to inches
If you have a measurement in decimal feet (like 3.5 feet), multiply by 12 the same way you would with a whole number. 3.5 × 12 = 42 inches. The decimal represents a portion of a foot, and multiplying by 12 converts that portion into inches just like it does for whole feet.
For example, 0.5 feet equals 6 inches (half a foot), and 0.25 feet equals 3 inches (one quarter of a foot). This method works for any decimal value, whether it is a straightforward fraction like 0.5 or a more complex decimal like 2.75 feet, which would equal 33 inches.
Why the conversion factor is always 12
The imperial measurement system, used in the United States and a few other countries, defines one foot as exactly 12 inches. This definition has been standardized for centuries and does not change based on context or process. Whether you are measuring a person's height, the length of a board, or the distance across a room, the relationship stays the same.
Other measurement systems, like the metric system used in most countries, do not use feet or inches at all. They use centimeters and meters instead, which relate to each other by factors of 10 or 100. But within the imperial system, 12 is the only conversion factor you will ever need for feet to inches, making the math straightforward and consistent.
Common situations where you need this conversion
Height is one of the most common reasons to convert feet to inches. A person who is 5 feet 10 inches tall is 70 inches tall. Builders and carpenters convert feet to inches when they need to work with smaller measurements or when a tool or material is marked in inches rather than feet.
Doorways, windows, and furniture are often described in feet, but installation instructions or measurements might be in inches. Converting between the two lets you compare measurements from different sources and make sure everything fits where it needs to go. Medical records, clothing sizes, and equipment specifications may also require you to switch between feet and inches depending on what information you are looking at.
Frequently Asked Questions
How do I convert 5 feet 7 inches to just inches?
Multiply 5 by 12 to get 60 inches, then add 7 inches for a total of 67 inches. You only multiply the feet portion by 12, then add any remaining inches to the result.
What if I have a fraction of a foot, like 2.75 feet?
Multiply 2.75 by 12 to get 33 inches. Decimals work the same way as whole numbers — the decimal represents a portion of a foot, and multiplying by 12 converts that portion into inches.
Can I convert inches back to feet?
Yes, divide the number of inches by 12. If you have 84 inches, divide by 12 to get 7 feet. If the division does not come out even, the remainder is the number of inches left over — for example, 75 inches divided by 12 equals 6 feet 3 inches.
Does this conversion work for all measurements?
Yes, the conversion works the same way whether you are measuring height, distance, length of an object, or any other dimension. One foot always equals 12 inches, so the multiplication method is reliable across all types of measurements.