How to Convert Feet to Inches

Feet to Inches Conversion Formula and How to Use It

When converting feet to inches, remember there are 12 inches in 1 foot.
When converting feet to inches, remember there are 12 inches in 1 foot. Image Source / Getty Images

Feet (ft) and inches (in) are two units of length, most commonly used in the United States. The units are used in schools, daily life, art, and some areas of science and engineering. The feet to inches conversion is useful and important, so here's the formula and examples that show how to convert feet to inches and inches to feet.

Feet to Inches Formula

This conversion isn't quite as easy as converting between metric units, which are simply factors of 10, but it's not difficult.

The conversion factor is:

1 foot = 12 inches

distance in inches = (distance in feet) x (12 inches/foot)

so, to convert a measurement in feet to inches, all you need to do is multiply the number by 12. This is an exact number, so if you're working with significant figures, it won't limit them.

Feet to Inches Example

Let's say you measure a room and find it is 12.2 feet across. Find the number in inches.

length in inches = length in feet x 12
length = 12.2 ft x 12
length = 146.4 or 146 inches

Converting Inches to Feet

Since all you do is multiply by 12 to convert feet to inches, it should make sense to you that all you do to convert inches to feet is divide by 12.

The conversion factor is the same:

12 inches = 1 foot

distance in feet = (distance in inches) / (12 inches/foot)

Inches to Feet Example

You measure your laptop and find the screen is 15.4 inches across. What is this in feet?

distance in feet = (distance in inches) / (12 inches/foot)
distance = 15.4 in / 12 in/ft
distance = 1.28 feet

Important Information for Unit Conversions with Division

One of the most common areas of confusion when doing unit conversions involving division concerns unit cancelling. When you're converting inches to feet, you divide by 12 in/ft. This is the same as multiplying by ft/in! It's one of those rules you use when multiplying fractions that a lot of people forget about when dealing with units.

When you divide by a fraction, the denominator (part on the bottom) moves to the top, while the numerator (part on the top) moves to the bottom. Thus, the units cancel out to give you the desired answer.