Enter inches as a whole number, decimal, or fraction to find the matching feet-and-inches measurement and decimal feet.
Advanced options
Table of contents
How to use our Inches to Feet and Inches Converter
- Enter the measurement in "Total length (inches)." You can type a whole number, decimal, fraction, or mixed number, such as 71, 18.5, 1/2, or 18 1/2.
- Select "Calculate" to see the feet-and-inches form first.
- Use "Length in decimal feet" only when a worksheet, formula, or software field asks for feet as one decimal number.
- If you need a different decimal-foot rounding, open "Advanced options" and change "Decimal feet places."
- Sanity-check the result: "Inches left after complete feet" should be at least 0 and less than 12.
Definitions
Total length: The full measurement in inches before it is split into feet and leftover inches.
Decimal feet: Feet written as one decimal number. For example, 1.5 ft equals 1 ft 6 in, not 1 ft 5 in.
Complete feet: The number of full 12-inch groups in the entered length.
Remaining inches: The amount left after complete feet are removed. For a nonnegative length, it is at least 0 and less than 12 inches.
Mixed number: A whole number plus a fraction, such as 18 1/2 inches.
Foot: A customary unit of length equal to exactly 12 inches.
Common mistakes and quick fixes
Mistake: Reading 5.5 feet as 5 ft 5 in.
Fix: A foot has 12 inches, not 10. Therefore, 5.5 ft is 5 ft 6 in.
Mistake: Typing a tape-measure fraction as separate numbers, such as 18 1 2.
Fix: Use a slash in the fraction: type 18 1/2.
Mistake: Entering a negative measurement.
Fix: Enter zero or a positive total length. This converter uses nonnegative lengths only.
Mistake: Using zero as the bottom number in a fraction, such as 1/0.
Fix: Use a denominator greater than zero. Division by zero is undefined.
Mistake: Rounding decimal feet before finding feet and inches.
Fix: Use the feet-and-inches answer shown first. The calculator splits the original inch measurement before rounding decimal feet for display.
Limitations & Key Assumptions / Boundary Conditions
- The converter accepts nonnegative lengths only; it does not represent direction, coordinates, or negative offsets.
- It converts the measurement entered and cannot check whether a ruler, tape measure, plan, or height record was read correctly.
- "Decimal feet places" changes displayed rounding only and does not change the feet-and-inches answer.
- A very small positive measurement may display as 0 decimal feet when few decimal places are selected; choose more places if that detail matters.
- The calculation uses the exact 12-inches-per-foot relationship and does not convert to metric units.
Methodology
Calculation
One foot equals exactly 12 inches, so the converter counts complete groups of 12 in the entered total.
whole_feet = floor(inches / 12)
remaining_inches = inches - whole_feet * 12
decimal_feet = inches / 12
The first answer combines the complete-foot count with the inches left over. Decimal feet are rounded only after the calculation.
Worked example
For 18 1/2 inches, one complete 12-inch foot fits. The remainder is 6 1/2 inches, so the first answer is 1 ft 6 1/2 in. The decimal-feet value is about 1.5417 ft.
18.5 / 12 = 1.541666...
The input can be a whole number, decimal, fraction, or mixed number, with an optional inch suffix. The converter rejects blank entries, negative lengths, malformed measurements, and fractions with a zero denominator.