Add, subtract, multiply and divide feet, inches and fractions to 1/16 inch, with cm and m
Runs in your browser. Nothing you type is sent anywhere. Checked against sources on 29 Sept 2026.Feet and inches add like any mixed units: add the fractions, then the inches, and carry every 12 inches into a foot. 5' 7 3/8" plus 2' 9 5/8" is 8' 5", which is 101 inches, 8.417 decimal feet or 256.54 cm. Results round to the nearest 1/16 inch.
Type the First length, such as 5' 7 3/8" or 5 ft 7 in; a number with no unit counts as inches.
Pick the Operation: +, minus, times, divide or Convert.
Type the Second length, or a plain number when you multiply or divide.
Choose a fraction under "Round fractions to", from 1/8" to 1/64".
Read the answer in feet and inches with Decimal feet and Centimeters, and open Every unit for the rest.
Measurements off a tape come in feet, inches and sixteenths, and adding them by hand means juggling three kinds of number at once. This calculator takes lengths the way you write them, does the arithmetic, and gives the answer back in the same form, reduced to the simplest fraction, alongside decimal feet, inches, centimeters, meters and millimeters.
Type it the way you say it. 5' 7 3/8", 5'7", 5'-7 3/8", 5 ft 7-3/8 in, 5.5 ft, 67 3/8 and 170 cm are all understood. A number with no unit is read as inches. The page shows how it read each value, so a typo is obvious before you cut.
Four operations and a plain conversion. Add and subtract two lengths; multiply a length by a number to repeat it; divide a length by a number to split it into equal parts; or divide a length by a length to see how many times one fits in the other, such as how many 16-inch spaces fit along a 12-foot wall (9). Choose "Convert" to change one length into every unit without any arithmetic.
Rounding you can see. The arithmetic is exact, and only the displayed fraction is rounded, to the nearest 1/16 inch by default, or 1/8, 1/32 or 1/64 if you prefer. When rounding changes the value, the page says by how much. Fractions are reduced, so 8/16 shows as 1/2.
Metric alongside. One inch is exactly 2.54 centimeters, by the international agreement the United States adopted in 1959, so one foot is exactly 30.48 cm. Metric results are shown to a tenth of a millimeter.
What this calculator does not do: it does not multiply two lengths into an area or three into a volume, and it does not work in yards and miles. For areas, volumes and materials, use the cubic yard, board foot or roof pitch calculators on this site.
Add the fractions first, then the inches, then the feet, carrying each 12 inches into one foot. For 5' 7 3/8" plus 2' 9 5/8", the fractions make 1 inch, the inches make 17 inches, or 1 foot 5 inches, and the feet make 7, so the total is 8 feet 5 inches.
Divide the inches by 12 and add the result to the feet. For 8 feet 5 inches, 5 divided by 12 is 0.4167, so the length is 8.417 decimal feet. A fraction of an inch goes into the inches first: 7 3/8 inches is 7.375 inches, or 0.6146 feet.
Exactly 2.54 centimeters, fixed by the international yard and pound agreement adopted by the United States in 1959. A foot is therefore exactly 30.48 centimeters, and a height of 5 feet 7 inches, which is 67 inches, is 170.18 centimeters.
Most tape measures are marked in sixteenths of an inch, so the answer is given to the nearest mark. One inch divided by 3 is 0.3333 inches, which rounds to 5/16, about 0.02 inches short. The calculator shows the difference whenever rounding changes a value, and offers 1/32 or 1/64 when more precision is needed.
Twelve feet is 144 inches, and 144 divided by 16 is exactly 9. To check any spacing, choose divide, enter the wall or run length first and the spacing with its inch mark second, such as 16", and the calculator returns how many times the spacing fits, including any fraction left over.
Yes. Enter a value with cm, m or mm, such as 170 cm or 1.2 m, and the calculator converts it to inches before doing the arithmetic, so you can add a metric part to an imperial measurement. Results always come back in feet, inches and fractions as well as metric.
Rates and rules change; check the source before you rely on a figure.
Still stuck? Ask about Feet and Inches Calculator and anybody who knows can answer. No account needed.
Same job, other tools: Add Days to a Date – Add days to a date: the date 30, 60 or 90 days, or weeks and months, from any date · Inches to CM Converter – Inches to centimeters and back: 1 inch is exactly 2.54 cm · Feet to Meters Converter – Feet to meters and back: 1 foot is exactly 0.3048 m, 1 meter 3.28084 feet · Shoe Size by Foot Length – Measure your foot in cm or inches and get your size in every system.
Also works as: Feet and Inches to CM.