Convert Mil to Chain
Convert mils to chains instantly. 1 mil = 1.262626e-6 chain — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Chain to Mil converter for the reverse conversion.
Units explained
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".
Chain
A chain is an Imperial unit of length equal to 66 feet (20.1168 m), or exactly 4 rods or 100 links. It is the central unit in the Gunter chain-based land-survey system.
Defined by Edmund Gunter in 1620 specifically to make land-area arithmetic easy: 10 square chains = 1 acre exactly. The 66-foot length and 100-link subdivision were chosen so chain measurements could be added decimally.
Chains are the fundamental unit of legacy US public land surveys (the entire US township-and-range system uses chains). Modern survey work generally uses meters or feet, but legacy deeds remain in chains.
Invented by Edmund Gunter in 1620; standardised throughout English and American land survey; became exact via the 1959 International Yard and Pound Agreement.
Mil to Chain conversion formula
The relationship between mils and chains:
To convert mils to chains, multiply the value in mils by 1.262626e-6. To reverse, multiply chains by 792000.
How to use this converter
Type a value into the calculator. The result in chains updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Chain to Mil converter for the reverse direction.
Step-by-step: convert mils to chains
- Write down the value in mils (mil).
- Multiply that value by the factor 1.262626e-6.
- The product is the equivalent value in chains (ch).
- To reverse, multiply the chain value by 792000.
Worked examples
Example 1 — Convert 1 mil to ch:
1 × 1.262626e-6 = 1.262626e-6 ch
Example 2 — Convert 100 mil to ch:
100 × 1.262626e-6 = 0.0001262626 ch
Real-world example — Hair-width scale measurements
A 70-mil measurement (about the diameter of a human hair) is the kind of value materials engineers regularly express in adjacent micro-scale units like chains for direct comparison across supplier datasheets.
70 mil × 1.262626e-6 = 8.838384e-5 ch
Real-world example — Paper and film thicknesses
At the thickness of office paper (roughly 3 mils), converting between sub-millimeter units is routine for packaging and printing buyers comparing quotes from metric and US suppliers.
3 mil × 1.262626e-6 = 3.787879e-6 ch
Real-world example — Plastic-film thickness alternates
A 150-mil plastic film converts cleanly to chains — useful for packaging buyers reconciling supplier datasheets across metric and US measurement systems.
150 mil × 1.262626e-6 = 0.0001893939 ch
Mil to Chain conversion table
Standard reference values for converting mils to chains:
| Mil [mil] | Chain [ch] |
|---|---|
| 0.01 | 1.262626e-8 |
| 0.1 | 1.262626e-7 |
| 1 | 1.262626e-6 |
| 2 | 2.525253e-6 |
| 3 | 3.787879e-6 |
| 4 | 5.050505e-6 |
| 5 | 6.313131e-6 |
| 10 | 1.262626e-5 |
| 20 | 2.525253e-5 |
| 30 | 3.787879e-5 |
| 40 | 5.050505e-5 |
| 50 | 6.313131e-5 |
| 100 | 0.0001262626 |
| 500 | 0.0006313131 |
| 1000 | 0.0012626263 |
Frequently asked questions
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Metric / SI (7 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Sources & references
Conversion factor (1 mil = 1.262626e-6 ch) 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.