Convert US Survey Foot to Mil
Convert us survey feet to mils instantly. 1 us survey foot = 12000.024000048 mil — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Mil 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.
Mil
A mil (also called a thou) is an Imperial unit of length equal to one thousandth of an inch (1/1000 in = 0.0254 mm = 25.4 μm exactly). It is used in engineering, manufacturing, and materials specifications.
The mil is derived from the Latin mille, "thousand," denoting one-thousandth of an inch. Standardized in industrial use during the 19th-century rise of precision engineering.
Mils are used to specify thicknesses of plastic films, foils, paper, copper traces on printed circuit boards (PCBs), wire insulation, and paint coatings. A standard sheet of paper is about 4 mils thick.
Adopted in 19th-century engineering practice; the value (1/1000 in) became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement. The British term is "thou"; American term is "mil".
US Survey Foot to Mil 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 mils:
To convert us survey feet to mils, multiply the value in us survey feet by 12000.024000048. To reverse, multiply mils by 8.333317e-5.
How to use this converter
Type a value into the calculator. The result in mils updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Mil to US Survey Foot converter for the reverse direction.
Step-by-step: convert us survey feet to mils
- Write down the value in us survey feet (sft).
- Multiply that value by the factor 12000.024000048.
- The product is the equivalent value in mils (mil).
- To reverse, multiply the mil value by 8.333317e-5.
Worked examples
Example 1 — Convert 1 sft to mil:
1 × 12000.024000048 = 12000.024000048 mil
Example 2 — Convert 100 sft to mil:
100 × 12000.024000048 = 1200002.4000048002 mil
Real-world example — Macroscopic to microscopic
One us survey foot equals a million mils. Optical engineers calculating coherence length compare macro-scale path lengths with micro-scale wavelength differences using exactly this conversion.
1 sft × 12000.024000048 = 12000.024000048 mil
Real-world example — Sub-meter precision
A 0.001-us survey foot (1 mm) tolerance equals 1,000 mils — useful for surface-finish specs, where macro-scale dimensions are given in the larger unit but feature roughness in the smaller.
0.001 sft × 12000.024000048 = 12.000024 mil
Real-world example — Macro-to-micro scale comparison
2 us survey feet of measurement converts to a very large number in mils — useful in materials science when comparing bulk-sample dimensions to feature-level surface specs.
2 sft × 12000.024000048 = 24000.048000096 mil
US Survey Foot to Mil conversion table
Standard reference values for converting us survey feet to mils:
| US Survey Foot [sft] | Mil [mil] |
|---|---|
| 0.01 | 120.0002400005 |
| 0.1 | 1200.0024000048 |
| 1 | 12000.024000048 |
| 2 | 24000.048000096 |
| 3 | 36000.072000144 |
| 4 | 48000.096000192 |
| 5 | 60000.12000024 |
| 10 | 120000.24000048 |
| 20 | 240000.48000096 |
| 30 | 360000.72000144 |
| 40 | 480000.96000192 |
| 50 | 600001.2000024001 |
| 100 | 1200002.4000048002 |
| 500 | 6000012.0000240002 |
| 1000 | 1.200002e+7 |
Frequently asked questions
How many mils is 1 us survey foot?
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How many mils is 100 us survey feet?
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Metric / SI (7 units)
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Nautical (1 units)
Sources & references
Conversion factor (1 sft = 12000.024000048 mil) 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.