Feet & Inches Calculator
Add, subtract, multiply and divide feet, inches and fractions — then convert to decimal inches, feet, mm, cm and metres
Type a measurement like 5' 3 1/2", 3 1/2", 5ft 3-1/2in, 1/2" or a plain number (taken as inches).
Accepted input formats
| Input | Means |
|---|---|
| 5' 3 1/2" | 5 ft + 3 1/2 in = 63.5 in |
| 5ft 3-1/2in | 5 ft + 3 1/2 in = 63.5 in |
| 3 1/2" | 3 1/2 in = 3.5 in |
| 1/2" | 1/2 in = 0.5 in |
| 6' | 6 ft = 72 in |
| 63.5 | 63.5 in (bare number = inches) |
Height conversion chart: feet and inches to cm
Convert a height in feet and inches to centimetres and metres. The chart below lists common heights from about 4 ft 6 in to 6 ft 6 in. One inch equals exactly 2.54 cm.
Common heights
| Feet & inches | Centimetres | Metres | Decimal inches |
|---|---|---|---|
| 4' 6" | 137.2 | 1.37 | 54 |
| 4' 7" | 139.7 | 1.4 | 55 |
| 4' 8" | 142.2 | 1.42 | 56 |
| 4' 9" | 144.8 | 1.45 | 57 |
| 4' 10" | 147.3 | 1.47 | 58 |
| 4' 11" | 149.9 | 1.5 | 59 |
| 5' 0" | 152.4 | 1.52 | 60 |
| 5' 1" | 154.9 | 1.55 | 61 |
| 5' 2" | 157.5 | 1.57 | 62 |
| 5' 3" | 160 | 1.6 | 63 |
| 5' 4" | 162.6 | 1.63 | 64 |
| 5' 5" | 165.1 | 1.65 | 65 |
| 5' 6" | 167.6 | 1.68 | 66 |
| 5' 7" | 170.2 | 1.7 | 67 |
| 5' 8" | 172.7 | 1.73 | 68 |
| 5' 9" | 175.3 | 1.75 | 69 |
| 5' 10" | 177.8 | 1.78 | 70 |
| 5' 11" | 180.3 | 1.8 | 71 |
| 6' 0" | 182.9 | 1.83 | 72 |
| 6' 1" | 185.4 | 1.85 | 73 |
| 6' 2" | 188 | 1.88 | 74 |
| 6' 3" | 190.5 | 1.91 | 75 |
| 6' 4" | 193 | 1.93 | 76 |
| 6' 5" | 195.6 | 1.96 | 77 |
| 6' 6" | 198.1 | 1.98 | 78 |
Heights are rounded to one decimal place. One inch equals exactly 2.54 centimetres (international inch).
About this calculator
This feet and inches calculator is built for the way trades and DIY work actually measure: feet, inches and binary fractions like 1/2, 1/4, 1/8 and 1/16 of an inch. Tape measures, cut lists and plans are full of values such as 5' 3 1/2", and adding or subtracting them by hand is fiddly because feet roll over at 12 inches and fractions need a common denominator. Type your measurements in plain notation — 5' 3 1/2", 3 1/2", 5ft 3-1/2in, 1/2" or just a number of inches — and the calculator adds, subtracts, multiplies or divides them and shows the answer as a clean ft' in fraction" reading rounded to the precision you choose (1/8, 1/16 or 1/32). It also converts any measurement to decimal inches, decimal feet, millimetres, centimetres and metres, so the same number works whether your drawing is imperial or metric. It is handy for carpentry, woodworking, flooring, framing, sewing, and any job where you cut to a fraction of an inch.
How to use
- 1 Choose a mode: Calculate to add, subtract, multiply or divide; Convert to read one measurement in every unit.
- 2 Type measurements in plain notation, for example 5' 3 1/2", 3 1/2", 5ft 3-1/2in, 1/2" or a bare number (inches).
- 3 Pick the fraction precision (1/8, 1/16 or 1/32) so the answer is rounded to the smallest fraction you use.
- 4 Read the result in feet & inches plus decimal inches, decimal feet, mm, cm and metres, and copy any value.
How it works
Every measurement you type is parsed into a single total in inches: a foot counts as 12 inches, a fraction a/b counts as a÷b inches, and a mixed value like 3 1/2 is 3 + 1/2. Adding and subtracting two measurements is then just adding or subtracting these totals; multiplying or dividing scales the total by your number. To display the answer the total is rounded to the nearest 1/8, 1/16 or 1/32 of an inch, split back into feet (÷12) and inches, and the leftover fraction is reduced to lowest terms using the greatest common divisor — so 8/16 becomes 1/2. Conversions to millimetres, centimetres and metres use the exact definition 1 inch = 25.4 mm, so 63.5 inches is exactly 1612.9 mm, 161.29 cm or 1.6129 m.
Frequently asked questions
How do I add feet and inches with fractions?
Type each measurement the way you would say it, for example 5' 3 1/2" and 2' 9 3/4", choose Add, and the calculator returns 8' 1 1/4". It works by converting everything to total inches (a foot is 12 inches, a fraction is just division), adding them, then converting back to feet, whole inches and a reduced fraction at the precision you pick.
What does the fraction precision (1/8, 1/16, 1/32) do?
It sets the smallest fraction the answer is rounded to. A standard tape measure usually reads to 1/16", so 1/16 is a good default; choose 1/8 for rougher work or 1/32 for fine joinery. The result is rounded to the nearest step and the fraction is reduced, so 8/16 is shown as 1/2.
Can I multiply or divide a measurement?
Yes. Choose Multiply or Divide and the second field becomes a plain number. For example 5' 3 1/2" × 2 = 10' 7", and 12' ÷ 3 = 4'. This is useful for spacing studs evenly, scaling a cut, or splitting a length into equal parts. Division by zero is not allowed.
How do I convert feet and inches to mm, cm or metres?
Switch to Convert, type a measurement such as 5' 3 1/2", and you get decimal inches, decimal feet, millimetres, centimetres and metres at once. The conversion uses the exact factor 1 inch = 25.4 mm, so 63.5 inches equals 1612.9 mm, 161.29 cm, or about 1.6129 m.
Related tools and uses
Pair this with the metal weight calculator for stock and the cooking converter for kitchen measures, and use the main unit converter for any other length conversion between imperial and metric.