FEET AND INCHES CALCULATOR
How it works
6 feet 9-1/2 inches plus 3 feet 4-3/4 inches.
- Add the inches first: 9-1/2" + 4-3/4" = 14-1/4".
- 14-1/4" is more than a foot, so carry 12 inches into the feet: 14-1/4" − 12" = 2-1/4", carry 1 foot.
- Add the feet, including the carry: 6' + 3' + 1' = 10'.
10' 2-1/4" — 122.25 inches, 10.1875 feet, or 3.105 metres.
Constants
| Constant | Value |
|---|---|
| Inches per foot | 12 in |
| Millimetres per inch | 25.4 mm |
| Display precision | nearest 1/16 in |
SOURCE — 1 foot = 12 inches, by definition.
SOURCE — 1 inch = 25.4 mm exactly, by international definition (1959).
SOURCE — the feet-inches format displays to the nearest 1/16 inch; the exact value is kept internally and never rounds twice.
Quick answers
6 feet 9-1/2 inches plus 3 feet 4-3/4 inches is 10' 2-1/4". The inches add first, and 12 of them carry into a foot exactly like carrying a digit in long addition.
8 feet 5-1/2 inches minus 2 feet 7-3/4 inches is 5 feet 9-3/4 inches — subtraction borrows a foot the same way addition carries one.
10' 2-1/4" is 122.25 inches, 10.1875 feet, or 3.105 metres — the same length, shown four ways.
Multiplying two lengths changes the unit: 5 feet times 4 feet is 20 square feet, not 20 feet — the tape is doing real math, not restating the input.
Dividing one length by another leaves no unit at all: 10 feet divided by 4 feet is 2.5, a plain ratio.
6 feet 2 inches is 74 decimal inches, 6.1667 feet, or 1.880 metres — the same conversion this calculator runs on every submeasurement.
FAQ
How do I add feet and inches?
Add the inches first, then the feet. If the inches total 12 or more, carry each whole foot into the feet column: 9-1/2" + 4-3/4" = 14-1/4", which carries as 1 foot 2-1/4 inches, for a running total of 10 feet 2-1/4 inches.
How do I subtract feet and inches?
Subtract the smaller inches from the larger; if the top inches are smaller, borrow 12 inches from the feet column first, the same way you would borrow ten in ordinary subtraction. 8 feet 5-1/2 inches minus 2 feet 7-3/4 inches is 5 feet 9-3/4 inches.
How do I multiply one length by another?
Multiplying two lengths produces an area, not a longer length: 5 feet times 4 feet is 20 square feet. The calculator promotes the unit automatically and shows the result in every area format.
How do I divide one measurement by another?
Dividing a length by a length leaves a plain number with no unit — 10 feet divided by 4 feet is 2.5. Dividing by zero is rejected outright rather than shown as an error value.
How does the tape fraction math stay exact?
Every measurement is stored as an exact fraction, not a rounded decimal, so nothing drifts across a chain of adds and subtracts. The only rounding happens once, at the display, to the nearest sixteenth.
What is 6 feet 2 inches in decimal inches or metres?
74 decimal inches, 6.1667 feet, or 1.880 metres. Multiply the whole feet by 12 and add the inches to get decimal inches, then convert from there.
Why does the result show four different numbers?
One measurement has four honest readings: the feet-inch-fraction the tape shows, its decimal-inch equivalent, its decimal-feet equivalent, and its metric equivalent. All four are exactly the same length, just written differently.