Feet to Inches (ft → in) – Exact Conversion Guide
Core idea: The relationship is exact: 1 foot = 12 inches. Multiply feet by 12 to get inches. Divide inches by 12 to get feet. No rounding needed unless you show decimals for fractional feet.
Formulas
in = ft × 12ft = in ÷ 12- Mixed (feet + inches to total inches):
totalIn = (ft × 12) + in
- Fractional feet from inches:
ft = in / 12
Quick Values
| Feet | Inches | Comment |
|---|
| 0.5 | 6 | Half foot |
| 1 | 12 | 1 foot |
| 2 | 24 | 2 feet |
| 5 | 60 | Common height base |
| 6 | 72 | 6-foot mark |
| 8 | 96 | Door rough stud height (US) |
Worked Example
Example: Convert 6 ft to inches.
in = 6 × 12 = 72 in. Exact—no rounding.
Where This Matters
- Carpentry & framing (stud spacing, trim lengths).
- Human height conversions to decimal for data entry.
- Sports specs (vertical leap, clearance heights).
- Manufacturing drawings converting between fractional & decimal formats.
Accuracy & Tips
- No approximation: 12 is exact.
- To get fractional inches from decimal feet: multiply decimal feet by 12 then break remainder into fractions (e.g., 5.75 ft → 69 in → 5 ft 9 in).
- To go decimal from feet-inches:
ftDecimal = ft + (in ÷ 12).
- Common fraction shortcuts: 0.25 ft = 3 in, 0.125 ft = 1.5 in.
More Examples
| Feet (ft) | Inches (in) | Feet & Inches Mixed |
|---|
| 2.5 | 30 | 2 ft 6 in |
| 5.5 | 66 | 5 ft 6 in |
| 5.75 | 69 | 5 ft 9 in |
| 6.25 | 75 | 6 ft 3 in |
| 7.5 | 90 | 7 ft 6 in |
FAQ
- Why 12 inches in a foot? Historical base-12 (duodecimal) convenience for division into halves, thirds, quarters.
- How many feet is 30 inches? 30 ÷ 12 = 2.5 ft.
- Convert 70 inches to feet + inches: 70 ÷ 12 = 5 ft remainder 10 → 5′10″.
- What is 5′11″ in total inches? (5 × 12) + 11 = 71 in.
All relationships exact; only decimal formatting introduces rounding choices.