Convert Square Millimeter to Microbarn
Convert square millimeters to microbarns instantly. 1 square millimeter = 1e+28 microbarn — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Microbarn to Square Millimeter converter for the reverse conversion.
Units explained
Square Millimeter
A square millimeter is a metric unit of area equal to 10⁻⁶ m² (1 mm × 1 mm). It is widely used in engineering, electronics, and small-scale technical work.
Derived by squaring the millimeter, defined as 1/1000 of a meter. The milli- prefix comes from the Latin 'mille' (thousand).
Square millimeters express PCB trace cross-sections, the area of small mechanical features in CAD drawings, biological sample sizes, and material thicknesses.
Millimeter has been part of the metric system since 1795.
Microbarn
A microbarn is a scientific unit of area equal to exactly 10⁻³⁴ m² (10⁻⁶ barn).
Derived from the barn using the standard SI micro- prefix. Identical in value to the humor unit 'outhouse'.
Microbarns appear in particle physics for moderately rare process cross-sections. They are widely used in heavy-ion physics and electroweak cross-section measurements.
Standard derivative of the barn unit.
Square Millimeter to Microbarn conversion formula
The relationship between square millimeters and microbarns:
To convert square millimeters to microbarns, multiply the value in square millimeters by 1e+28. To reverse, multiply microbarns by 1e-28.
How to use this converter
Type a value into the calculator. The result in microbarns updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Microbarn to Square Millimeter converter for the reverse direction.
Step-by-step: convert square millimeters to microbarns
- Write down the value in square millimeters (mm²).
- Multiply that value by the factor 1e+28.
- The product is the equivalent value in microbarns (µb).
- To reverse, multiply the microbarn value by 1e-28.
Worked examples
Example 1 — Convert 1 mm² to µb:
1 × 1e+28 = 1e+28 µb
Example 2 — Convert 100 mm² to µb:
100 × 1e+28 = 1e+30 µb
Real-world example — From microns to sub-micron features
One square millimeter equals one thousand microbarns — the conversion semiconductor designers do constantly when comparing mask feature dimensions to actual transistor gate lengths.
1 mm² × 1e+28 = 1e+28 µb
Real-world example — Infrared to visible-spectrum mapping
A 10-square millimeter thermal infrared wavelength corresponds to a much larger number in microbarns, the unit favoured for ultraviolet and visible-light specifications.
10 mm² × 1e+28 = 1e+29 µb
Real-world example — Mid-micron to nanometer
3 square millimeters equals 3,000 microbarns — useful when relating mid-infrared wavelengths (typically quoted in microns) to nanometer-scale visible-light wavelength tables.
3 mm² × 1e+28 = 3e+28 µb
Square Millimeter to Microbarn conversion table
Standard reference values for converting square millimeters to microbarns:
| Square Millimeter [mm²] | Microbarn [µb] |
|---|---|
| 0.01 | 1e+26 |
| 0.1 | 1e+27 |
| 1 | 1e+28 |
| 2 | 2e+28 |
| 3 | 3e+28 |
| 4 | 4e+28 |
| 5 | 5e+28 |
| 10 | 1e+29 |
| 20 | 2e+29 |
| 30 | 3e+29 |
| 40 | 4e+29 |
| 50 | 5e+29 |
| 100 | 1e+30 |
| 500 | 5e+30 |
| 1000 | 1e+31 |
Frequently asked questions
How many microbarns is 1 square millimeter?
How do I convert square millimeters to microbarns?
How do I convert microbarns back to square millimeters?
How many microbarns is 100 square millimeters?
Popular area unit conversions
Convert Square Millimeter to other area units
Show all Square Millimeter conversions
Metric / SI (15 units)
Imperial / US Customary (15 units)
US Survey (5 units)
Indian Subcontinent (16 units)
Other Regional (10 units)
Scientific / Physics (5 units)
Sources & references
Conversion factor (1 mm² = 1e+28 µb) 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.