Decimal inches to fraction calculator
Tape measures are marked in sixteenths. This rounds a decimal to the nearest mark and writes it out properly.
Feet and inches
2' 3 11/16"
- Inches as a fraction
- 3 11/16
- Whole feet
- 2
- In millimetres
- 703.263 mm
- Rounding error
- 0 in
Show the working
- Decimal inches = 27.6875
- Precision = 16
- ticks = round(27.6875 * 16) = 443
- Feet and inches = 443 / 16 = 27.6875
- Whole feet = floor(27.6875 / 12) = 2
- Inches as a fraction = 27.6875 - 2*12 = 3.6875
- In millimetres = 27.6875 * 25.4 = 703.263
- Rounding error = 27.6875 - 27.6875 = 0
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
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The formula
- nearest mark = round(inches x denominator) / denominator
- 1 inch = 25.4 mm exactly
The inch has been exactly 25.4 mm since the 1959 international yard and pound agreement.