Convert Mil to Barleycorn
Convert mils to barleycorns instantly. 1 mil = 0.003 barleycorn — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Barleycorn 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".
Barleycorn
A barleycorn is an Imperial unit of length equal to one third of an inch (about 8.47 mm). It is the basis of UK shoe sizing and is one of the oldest English length units still in use.
The barleycorn derives from the average length of a grain of barley as a natural reference. Standardised at exactly 1/3 inch by the Statute of Edward II in 1324, which used three barleycorns to define an inch.
Barleycorns are the foundation of UK and US children's shoe sizing — each whole size differs by one barleycorn. Also occasionally referenced in horse-handling and historical English literature.
Standardised in 1324 by the Statute of Edward II at 1/3 inch; the value became exact in 1959 when the inch was fixed at 25.4 mm.
Mil to Barleycorn conversion formula
The relationship between mils and barleycorns:
To convert mils to barleycorns, multiply the value in mils by 0.003. To reverse, multiply barleycorns by 333.3333346457.
How to use this converter
Type a value into the calculator. The result in barleycorns updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Barleycorn to Mil converter for the reverse direction.
Step-by-step: convert mils to barleycorns
- Write down the value in mils (mil).
- Multiply that value by the factor 0.003.
- The product is the equivalent value in barleycorns (barleycorn).
- To reverse, multiply the barleycorn value by 333.3333346457.
Worked examples
Example 1 — Convert 1 mil to barleycorn:
1 × 0.003 = 0.003 barleycorn
Example 2 — Convert 100 mil to barleycorn:
100 × 0.003 = 0.2999999988 barleycorn
Real-world example — Plastic film and laminate thickness
A 500-mil sheet is a typical spec for ID-card laminates and film overlays. Converting to barleycorns aligns the value with the unit most CAD systems and material datasheets prefer.
500 mil × 0.003 = 1.4999999941 barleycorn
Real-world example — Packaging gauge
A 4-mil plastic bag thickness is a common spec for grocery and freezer bags. Converting from mils to barleycorns is what packaging buyers do whenever they bridge US and metric supplier quotes.
4 mil × 0.003 = 0.012 barleycorn
Mil to Barleycorn conversion table
Standard reference values for converting mils to barleycorns:
| Mil [mil] | Barleycorn [barleycorn] |
|---|---|
| 0.01 | 3e-5 |
| 0.1 | 0.0003 |
| 1 | 0.003 |
| 2 | 0.006 |
| 3 | 0.009 |
| 4 | 0.012 |
| 5 | 0.0149999999 |
| 10 | 0.0299999999 |
| 20 | 0.0599999998 |
| 30 | 0.0899999996 |
| 40 | 0.1199999995 |
| 50 | 0.1499999994 |
| 100 | 0.2999999988 |
| 500 | 1.4999999941 |
| 1000 | 2.9999999882 |
Frequently asked questions
How many barleycorns is 1 mil?
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How many barleycorns is 100 mils?
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Sources & references
Conversion factor (1 mil = 0.003 barleycorn) 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.