Convert US Survey Foot to Microinch
Convert us survey feet to microinches instantly. 1 us survey foot = 1.200002e+7 microinch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Microinch to US Survey Foot converter for the reverse conversion.
Units explained
US Survey Foot
The US Survey Foot is a legacy unit of length defined as exactly 1200/3937 meters (approximately 0.3048006 m). It differs from the modern international foot by about 2 parts per million.
Established in the United States by the Mendenhall Order of 1893, which defined the foot in terms of the meter as 1200/3937 m. The US continued using this value for surveying even after the 1959 International Yard and Pound Agreement standardized the international foot at exactly 0.3048 m.
Used in US land surveying, geodetic measurements, state plane coordinate systems, and legal land descriptions. The US Survey Foot was officially deprecated by NIST and NOAA effective December 31, 2022, with the international foot becoming the sole US standard. Legacy data and recorded land surveys still reference it.
Mendenhall Order of 1893 defined the foot as 1200/3937 m; persisted in US surveying after 1959; officially deprecated by NIST/NOAA as of December 31, 2022.
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.
US Survey Foot to Microinch conversion formula
Note: this conversion uses a generally accepted modern value. Historical and regional definitions of this unit varied across times and places.
The relationship between us survey feet and microinches:
To convert us survey feet to microinches, multiply the value in us survey feet by 1.200002e+7. To reverse, multiply microinches by 8.333317e-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 US Survey Foot converter for the reverse direction.
Step-by-step: convert us survey feet to microinches
- Write down the value in us survey feet (sft).
- Multiply that value by the factor 1.200002e+7.
- The product is the equivalent value in microinches (µin).
- To reverse, multiply the microinch value by 8.333317e-8.
Worked examples
Example 1 — Convert 1 sft to µin:
1 × 1.200002e+7 = 1.200002e+7 µin
Example 2 — Convert 100 sft to µin:
100 × 1.200002e+7 = 1.200002e+9 µin
Real-world example — Meter to nanoscale
One us survey foot equals one billion microinches. Physics curricula use this conversion to teach orders of magnitude when introducing the electromagnetic spectrum.
1 sft × 1.200002e+7 = 1.200002e+7 µin
Real-world example — Human-scale to atomic dimensions
One us survey foot equals one billion microinches — the canonical metric conversion bridging everyday objects and atomic-scale features in physics, chemistry, and electronics.
1 sft × 1.200002e+7 = 1.200002e+7 µin
US Survey Foot to Microinch conversion table
Standard reference values for converting us survey feet to microinches:
| US Survey Foot [sft] | Microinch [µin] |
|---|---|
| 0.01 | 120000.24000048 |
| 0.1 | 1200002.4000048002 |
| 1 | 1.200002e+7 |
| 2 | 2.400005e+7 |
| 3 | 3.600007e+7 |
| 4 | 4.80001e+7 |
| 5 | 6.000012e+7 |
| 10 | 1.200002e+8 |
| 20 | 2.400005e+8 |
| 30 | 3.600007e+8 |
| 40 | 4.80001e+8 |
| 50 | 6.000012e+8 |
| 100 | 1.200002e+9 |
| 500 | 6.000012e+9 |
| 1000 | 1.200002e+10 |
Frequently asked questions
How many microinches is 1 us survey foot?
How do I convert us survey feet to microinches?
How do I convert microinches back to us survey feet?
How many microinches is 100 us survey feet?
Popular length unit conversions
Convert US Survey Foot to other length units
Show all US Survey Foot conversions
Metric / SI (7 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Sources & references
Conversion factor (1 sft = 1.200002e+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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.