Feet to Inches — Length Conversion Guide

One foot is exactly $12$ inches, so converting feet to inches is a single multiplication: multiply the number of feet by $12$.

The formula and its symbols

which gives the conversion rule

Here "feet" is the starting measurement and the result is in inches. This works for whole numbers and decimal values alike, as long as the starting unit is feet.

Why multiplying by 12 works

A foot is defined as $12$ inches, so each foot contains $12$ equal inch units. Two feet is therefore $2 \times 12 = 24$ inches. The same logic carries over to decimals: $5.5$ feet means $5.5$ groups of $12$ inches.

Worked example: convert 5.5 feet

Use the formula:

Multiply:

so

This example is worth doing because it shows how decimal feet behave. Half a foot is $6$ inches, so $5.5$ feet is $5$ feet plus $6$ inches, which matches $66$ inches.

Practice it yourself, then check

Convert $3.25$ feet, then convert $7$ feet $9$ inches, and compare the two methods.

Check your work: $3.25 \times 12 = 39$ inches. For $7$ feet $9$ inches, convert the feet part first ($7 \times 12 = 84$) and add the leftover inches ($84 + 9 = 93$ inches). Notice that the mixed form is handled differently from a decimal.

How to convert 5 feet 6 inches

A measurement written in mixed form, such as $5$ feet $6$ inches, is not the same as $5.6$ feet. Handle it in three steps:

1. Convert the feet part to inches.
2. Keep the extra inches.
3. Add them together.

For $5$ feet $6$ inches:

So $5$ feet $6$ inches equals $66$ inches.

Calculation traps

Confusing $5.6$ feet with $5$ feet $6$ inches. These are different measurements:

but $5$ feet $6$ inches is $66$ inches. Decimal feet and mixed feet-and-inches notation mean different things.

Treating the conversion as approximate. For standard feet and inches, $1$ foot equals exactly $12$ inches. It is not an estimate.

Leaving the final unit unclear. After multiplying by $12$, the answer is in inches, not feet. Writing the unit matters.

A quick sanity check before moving on: if the number of feet is greater than $1$, the inches should be greater than $12$; if the feet include a half, the inches should include an extra $6$; and converting from feet to a smaller unit should make the number larger.

Where this conversion shows up

Feet-to-inches conversion appears in everyday measurement, construction, furniture dimensions, room planning, and height measurements. It is especially useful when you need one unit throughout a calculation instead of mixing feet and inches in the same line of work. If a later formula expects inches, converting first usually keeps the rest of the problem clean.