# Feet and Inches Calculator

> Type two lengths the way you write them, such as 5' 3 1/2" and 2' 7 3/4", pick add, subtract, multiply, divide or how many fit, and read the answer in feet and inches, decimals and millimeters. You can also add up a list. 5' 3 1/2" plus 2' 7 3/4" is 7' 11 1/4".

Canonical: https://receiptscanner.co/tools/feet-and-inches-calculator
Updated: 2026-10-28 · Sources re-checked by: 2027-10-28

This is a free interactive calculator that runs in the browser. Nothing you type is stored or sent. Results are estimates.

## How it works

Every length is turned into inches first: feet × 12 plus inches plus the fraction. Add and subtract work on the inches. To multiply or divide, the length is multiplied or divided by a plain number. How many fit divides one length by another, rounds down to whole pieces and shows what is left. The answer is rounded to the nearest fraction you choose, from 1/2 down to 1/64 of an inch, and shown as feet and inches, as decimal feet and inches, and in millimeters, centimeters and meters (1 inch = 25.4 mm exactly).

**Fractions of an inch as decimals and millimeters**

| Fraction | Decimal inches | Millimeters |
| --- | --- | --- |
| 1/16 | 0.0625 | 1.59 |
| 1/8 | 0.125 | 3.18 |
| 3/16 | 0.1875 | 4.76 |
| 1/4 | 0.25 | 6.35 |
| 3/8 | 0.375 | 9.52 |
| 1/2 | 0.5 | 12.7 |
| 5/8 | 0.625 | 15.88 |
| 3/4 | 0.75 | 19.05 |
| 7/8 | 0.875 | 22.22 |
| 15/16 | 0.9375 | 23.81 |

**Inches as feet**

| Inches | Feet and inches | Decimal feet |
| --- | --- | --- |
| 6" | 6" | 0.5 |
| 18" | 1' 6" | 1.5 |
| 30" | 2' 6" | 2.5 |
| 42" | 3' 6" | 3.5 |
| 66" | 5' 6" | 5.5 |
| 90" | 7' 6" | 7.5 |
| 144" | 12' 0" | 12 |

## Worked examples: five common jobs

1. Add: 5' 3 1/2" is 63.5 in and 2' 7 3/4" is 31.75 in. Together 95.25 in = 7' 11 1/4", which is 7.9375 ft or 2,419.35 mm.
2. Subtract: 10' is 120 in and 3' 4 5/8" is 40.625 in. The difference is 79.375 in = 6' 7 3/8".
3. Multiply: 8' 3" is 99 in, times 3 is 297 in = 24' 9".
4. Divide: 10' 3" is 123 in, divided by 5 is 24.6 in, which rounds to 2' 0 5/8" at 1/16 in.
5. Fit: 12' 6" is 150 in, divided by 16 in is 9 whole pieces with 6" left. A list of 2 × 8' 3", 3 × 5' 6 1/2" and 1 × 2' 9" adds up to 35' 10 1/2".

## FAQ

### How do I add feet and inches?
Change each length to inches, add them, then change the total back: 12 inches make a foot. For 5' 3 1/2" plus 2' 7 3/4", the inches add to 95.25, which is 7' 11 1/4". The calculator does this and keeps the fractions.

### How do I type a length?
Any common way works: 5' 3 1/2", 5 ft 3 1/2 in, 5'3-1/2", or just 63.5 for inches. You can also type 3 m or 30 cm and it converts.

### How do I subtract feet and inches?
Subtract the inches, then convert the result back. If the answer is negative the calculator shows a minus sign, which means the second length is the longer one.

### How do I divide a length into equal parts?
Choose divide and type the number of parts. 10' 3" divided by 5 gives 2' 0 5/8" for each part at 1/16 in. Set a finer fraction if you need more precision.

### How many pieces fit in a length?
Choose how many fit, type the length and the piece size. 12' 6" holds nine 16" pieces with 6" left over, which is handy for studs, pickets and tiles.

### What fraction should I round to?
Most tape measures show 1/16 of an inch, so 1/16 is a good default. Rough framing is often fine at 1/8, and fine woodwork may want 1/32 or 1/64.

## Sources

- [Foot (unit): 1 foot = 12 inches = 0.3048 meters exactly](https://en.wikipedia.org/wiki/Foot_(unit)) (checked 2026-10-28)
- [Inch: 1 inch = 25.4 millimeters exactly, and the fractions used on a tape measure](https://en.wikipedia.org/wiki/Inch) (checked 2026-10-28)
- [International yard and pound agreement (1959): the exact definitions of the inch and the foot](https://en.wikipedia.org/wiki/International_yard_and_pound) (checked 2026-10-28)

This calculator is an aid for planning. Always check measurements on the job, and remember that real boards and tape measures have small errors. Round to the fraction your work needs.