Convert Square Microinch to Square Thou
Convert square microinches to square thous instantly. 1 square microinch = 1e-6 square thou — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Thou to Square Microinch converter for the reverse conversion.
Units explained
Square Microinch
A square microinch is an imperial unit of area equal to 6.4516×10⁻¹⁶ m². It is used in precision-engineering contexts where surface roughness is measured in microinches.
Derived by squaring the microinch (1 µin = 25.4 nm). Standardized via the 1959 International Yard and Pound Agreement which defined 1 inch = 25.4 mm exactly.
Square microinches appear in surface metrology and high-precision manufacturing in countries that use imperial units, though more often surface roughness is reported as a length parameter (Ra) rather than as an area.
Standardized via the 1959 International Yard and Pound Agreement.
Square Thou
A square thou is an imperial unit of area equal to 6.4516×10⁻¹⁰ m², identical to the square mil. The word 'thou' is short for 'thousandth' (of an inch).
Identical in value to the square mil; 'thou' is the British engineering term, 'mil' is the American term. Both refer to 1/1000 of an inch.
Square thous are used in British and Commonwealth engineering contexts where 'thou' is preferred over 'mil', particularly in mechanical engineering tolerance specifications.
Standardized via the 1959 International Yard and Pound Agreement.
Square Microinch to Square Thou conversion formula
The relationship between square microinches and square thous:
To convert square microinches to square thous, multiply the value in square microinches by 1e-6. To reverse, multiply square thous by 999999.9999999999.
How to use this converter
Type a value into the calculator. The result in square thous updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Square Thou to Square Microinch converter for the reverse direction.
Step-by-step: convert square microinches to square thous
- Write down the value in square microinches (µin²).
- Multiply that value by the factor 1e-6.
- The product is the equivalent value in square thous (thou²).
- To reverse, multiply the square thou value by 999999.9999999999.
Worked examples
Example 1 — Convert 1 µin² to thou²:
1 × 1e-6 = 1e-6 thou²
Example 2 — Convert 100 µin² to thou²:
100 × 1e-6 = 0.0001 thou²
Real-world example — Molecular dimensions
The diameter of small molecular structures (around 2 square microinches) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.
2 µin² × 1e-6 = 2e-6 thou²
Real-world example — Wavelengths across the spectrum
Optical and atomic-scale phenomena are routinely cross-converted between sub-micron units. A photon of wavelength 800 square microinches can be re-expressed in square thous for direct comparison with another instrument's calibration data sheet.
800 µin² × 1e-6 = 0.0008 thou²
Square Microinch to Square Thou conversion table
Standard reference values for converting square microinches to square thous:
| Square Microinch [µin²] | Square Thou [thou²] |
|---|---|
| 0.01 | 1e-8 |
| 0.1 | 1e-7 |
| 1 | 1e-6 |
| 2 | 2e-6 |
| 3 | 3e-6 |
| 4 | 4e-6 |
| 5 | 5e-6 |
| 10 | 1e-5 |
| 20 | 2e-5 |
| 30 | 3e-5 |
| 40 | 4e-5 |
| 50 | 5e-5 |
| 100 | 0.0001 |
| 500 | 0.0005 |
| 1000 | 0.001 |
Frequently asked questions
How many square thous is 1 square microinch?
How do I convert square microinches to square thous?
How do I convert square thous back to square microinches?
How many square thous is 100 square microinches?
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Metric / SI (5 units)
Imperial / US Customary (14 units)
Sources & references
Conversion factor (1 µin² = 1e-6 thou²) 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.