Convert Square Inch to Barn
Convert square inches to barns instantly. 1 square inch = 6.4516e+24 barn — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Barn to Square Inch converter for the reverse conversion.
Units explained
Square Inch
A square inch is an imperial unit of area equal to exactly 0.00064516 m², the area of a square with sides of one inch. It is widely used in the United States for small-area measurements.
Derived by squaring the inch. The inch was standardized to exactly 25.4 mm via the 1959 International Yard and Pound Agreement.
Square inches are used extensively in US engineering, manufacturing, real estate (for floor plans), and everyday small-area measurements. Engine displacement is often expressed in cubic inches but cross-sections in square inches.
Inch dates to medieval English usage; modern exact value standardized in 1959.
Barn
A barn is a scientific unit of area equal to exactly 10⁻²⁸ m² (100 fm²). It is used in nuclear and particle physics to express interaction cross-sections.
Named in 1942 at Purdue University by physicists working on the Manhattan Project. The name comes from the phrase 'big as a barn' — uranium nuclei have cross-sections this large, which physicists initially considered surprisingly large for nuclear targets.
Barns and their submultiples (millibarn, microbarn, nanobarn, picobarn, femtobarn) are the standard units for cross-section measurements in nuclear physics, high-energy physics, and accelerator experiments. The Higgs boson production cross-section at the LHC is in the picobarn range.
Named in 1942 during the Manhattan Project; adopted internationally in particle physics.
Square Inch to Barn conversion formula
The relationship between square inches and barns:
To convert square inches to barns, multiply the value in square inches by 6.4516e+24. To reverse, multiply barns by 1.550003e-25.
How to use this converter
Type a value into the calculator. The result in barns updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Barn to Square Inch converter for the reverse direction.
Step-by-step: convert square inches to barns
- Write down the value in square inches (in²).
- Multiply that value by the factor 6.4516e+24.
- The product is the equivalent value in barns (b).
- To reverse, multiply the barn value by 1.550003e-25.
Worked examples
Example 1 — Convert 1 in² to b:
1 × 6.4516e+24 = 6.4516e+24 b
Example 2 — Convert 100 in² to b:
100 × 6.4516e+24 = 6.4516e+26 b
Real-world example — From microns to sub-micron features
One square inch equals one thousand barns — the conversion semiconductor designers do constantly when comparing mask feature dimensions to actual transistor gate lengths.
1 in² × 6.4516e+24 = 6.4516e+24 b
Real-world example — Infrared to visible-spectrum mapping
A 10-square inch thermal infrared wavelength corresponds to a much larger number in barns, the unit favoured for ultraviolet and visible-light specifications.
10 in² × 6.4516e+24 = 6.4516e+25 b
Real-world example — Mid-micron to nanometer
3 square inches equals 3,000 barns — useful when relating mid-infrared wavelengths (typically quoted in microns) to nanometer-scale visible-light wavelength tables.
3 in² × 6.4516e+24 = 1.93548e+25 b
Square Inch to Barn conversion table
Standard reference values for converting square inches to barns:
| Square Inch [in²] | Barn [b] |
|---|---|
| 0.01 | 6.4516e+22 |
| 0.1 | 6.4516e+23 |
| 1 | 6.4516e+24 |
| 2 | 1.29032e+25 |
| 3 | 1.93548e+25 |
| 4 | 2.58064e+25 |
| 5 | 3.2258e+25 |
| 10 | 6.4516e+25 |
| 20 | 1.29032e+26 |
| 30 | 1.93548e+26 |
| 40 | 2.58064e+26 |
| 50 | 3.2258e+26 |
| 100 | 6.4516e+26 |
| 500 | 3.2258e+27 |
| 1000 | 6.4516e+27 |
Frequently asked questions
How many barns is 1 square inch?
How do I convert square inches to barns?
How do I convert barns back to square inches?
How many barns is 100 square inches?
Popular area unit conversions
Convert Square Inch to other area units
Show all Square Inch conversions
Metric / SI (16 units)
Imperial / US Customary (14 units)
US Survey (5 units)
Indian Subcontinent (16 units)
Other Regional (10 units)
Scientific / Physics (5 units)
Historical / Pre-metric European (6 units)
Sources & references
Conversion factor (1 in² = 6.4516e+24 b) 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.