Convert Foot to Microinch
Convert feet to microinches instantly. 1 foot = 1.2e+7 microinch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Microinch to Foot converter for the reverse conversion.
Units explained
Foot
A foot is an Imperial and US customary unit of length equal to 12 inches or exactly 0.3048 meters. It is the most commonly used unit of length in everyday measurement in the United States.
The foot's origin is literally the length of a human foot, used as a measurement standard since antiquity. The English foot was standardized at various points in history; the modern international foot (0.3048 m exactly) was fixed by the 1959 International Yard and Pound Agreement.
Feet are used in the US for body height, building dimensions, room sizes, road sign clearances, aviation altitude (feet above sea level), and most everyday distance estimation. The UK uses feet informally for height despite officially being metric.
Used since antiquity; standardized to 0.3048 m exactly by the International Yard and Pound Agreement of 1959. Aviation worldwide uses feet for altitude despite metric adoption elsewhere.
Microinch
A microinch is an Imperial unit of length equal to one millionth of an inch (2.54×10⁻⁸ m). It is used almost exclusively in surface-finish specifications for precision machining and optical components.
The microinch is derived from the inch using the SI-style prefix micro- to denote one millionth. Standardised through the 1959 International Yard and Pound Agreement, which fixed the inch at exactly 25.4 mm.
Microinches express surface roughness (Ra values) in US-based precision manufacturing — typical machined surfaces are 16–125 µin. Optical components and bearing races are often specified to 1–4 µin Ra.
Used in US precision-manufacturing literature throughout the 20th century; value became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement.
Foot to Microinch conversion formula
The relationship between feet and microinches:
To convert feet to microinches, multiply the value in feet by 1.2e+7. To reverse, multiply microinches by 8.333333e-8.
How to use this converter
Type a value into the calculator. The result in microinches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Microinch to Foot converter for the reverse direction.
Step-by-step: convert feet to microinches
- Write down the value in feet (ft).
- Multiply that value by the factor 1.2e+7.
- The product is the equivalent value in microinches (µin).
- To reverse, multiply the microinch value by 8.333333e-8.
Worked examples
Example 1 — Convert 1 ft to µin:
1 × 1.2e+7 = 1.2e+7 µin
Example 2 — Convert 100 ft to µin:
100 × 1.2e+7 = 1.2e+9 µin
Real-world example — Human-scale to atomic dimensions
One foot equals one billion microinches — the canonical metric conversion bridging everyday objects and atomic-scale features in physics, chemistry, and electronics.
1 ft × 1.2e+7 = 1.2e+7 µin
Real-world example — Meter to nanoscale
One foot equals one billion microinches. Physics curricula use this conversion to teach orders of magnitude when introducing the electromagnetic spectrum.
1 ft × 1.2e+7 = 1.2e+7 µin
Foot to Microinch conversion table
Standard reference values for converting feet to microinches:
| Foot [ft] | Microinch [µin] |
|---|---|
| 0.01 | 120000 |
| 0.1 | 1200000.0000000002 |
| 1 | 1.2e+7 |
| 2 | 2.4e+7 |
| 3 | 3.6e+7 |
| 4 | 4.8e+7 |
| 5 | 6e+7 |
| 10 | 1.2e+8 |
| 20 | 2.4e+8 |
| 30 | 3.6e+8 |
| 40 | 4.8e+8 |
| 50 | 6e+8 |
| 100 | 1.2e+9 |
| 500 | 6e+9 |
| 1000 | 1.2e+10 |
Frequently asked questions
How many microinches is 1 foot?
How do I convert feet to microinches?
How do I convert microinches back to feet?
How many microinches is 100 feet?
Popular length unit conversions
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Metric / SI (18 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 ft = 1.2e+7 µin) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.