Feet to Inches Converter
Convert feet (ft) to inches (in) using documented conversion factors. Includes interactive calculations, conversion formula, worked steps, and common reference tables.
Live Interactive Calculator
inch = foot × 12Conversion Formula
To convert from feet to inches, apply the mathematical formula:
Where ft represents feet and in represents inches.
Conversion Factor
The base relationship defined under primary measurement standards:
Reference: NIST SP 811 (1959 International Yard and Pound Agreement)
International Length Standards & Exact Definitions
All modern length units are legally tied to the metric base unit, the meter (m), defined by the BIPM as the distance traveled by light in a vacuum during an interval of 1/299,792,458 of a second.
Under the 1959 International Yard and Pound Agreement, English and US customary measurements are exact fractions of the meter:
Because these definitions are exact, conversions between yards, feet, inches, centimeters, and meters have zero theoretical error.
How to Convert Feet to Inches
Converting measurements between feet and inches follows a structured calculation process:
- Identify the quantity in feet (ft) that you wish to convert.
- Multiply the input by the conversion factor ratio
1 ft = 12 in. - The resulting value is the equivalent amount expressed in inches (in).
Common Feet to Inches Reference Table
Frequently referenced values calculated using documented measurement conversion factors.
| Foot (ft) | Inch (in) | Arithmetic Expression |
|---|---|---|
| 0.5 ft | 6 in | 0.5 × 12 |
| 1 ft | 12 in | 1 × 12 |
| 2 ft | 24 in | 2 × 12 |
| 3 ft | 36 in | 3 × 12 |
| 4 ft | 48 in | 4 × 12 |
| 5 ft | 60 in | 5 × 12 |
| 5.5 ft | 66 in | 5.5 × 12 |
| 5.8 ft | 69.6 in | 5.8 × 12 |
| 6 ft | 72 in | 6 × 12 |
| 6.2 ft | 74.4 in | 6.2 × 12 |
| 7 ft | 84 in | 7 × 12 |
| 8 ft | 96 in | 8 × 12 |
| 9 ft | 108 in | 9 × 12 |
| 10 ft | 120 in | 10 × 12 |
| 12 ft | 144 in | 12 × 12 |
| 15 ft | 180 in | 15 × 12 |
| 20 ft | 240 in | 20 × 12 |
Worked Calculation Examples
Practical step-by-step calculations showing how to convert feet to inches with exact mathematical equations.
Application context: 1 foot equals exactly 12 inches
Application context: Typical human height (5 ft 9 in = 69 in)
Application context: Standard ceiling height in modern residential homes
Application context: Regulation basketball rim height (120 inches)
About the Units
Authoritative technical specifications and historical definitions for both units.
Foot (ft)
A unit of length in the imperial and US customary systems of measurement, equal to 12 inches or 1/3 yard. Defined as exactly 0.3048 meters.
Inch (in)
A customary unit of length equal to 1/12 of a foot or 1/36 of a yard. Defined as exactly 25.4 millimeters (0.0254 meters).
Need to convert Inches back to Feet?
Reverse Formula: foot = inch ÷ 12
Related Length Converters
Contextual conversions related to this pair within the measurement graph.