Convert Chō to Square Millimeter
Convert chōs to square millimeters instantly. 1 chō = 9.91736e+9 square millimeter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Millimeter to Chō converter for the reverse conversion.
Units explained
Chō
A chō is a Japanese unit of large-scale area equal to approximately 9917.36 m² (about 0.991 hectare or 2.45 acres). It equals 3,000 tsubo.
Traditional Japanese land area unit, used historically for rice paddies and large estates.
Chōs appear in Japanese agricultural records and historical land documents. Modern usage favors hectares for new transactions but legacy records remain.
Traditional Japanese unit; standardized via the tsubo definition.
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.
Chō to Square Millimeter conversion formula
The relationship between chōs and square millimeters:
To convert chōs to square millimeters, multiply the value in chōs by 9.91736e+9. To reverse, multiply square millimeters by 1.008333e-10.
How to use this converter
Type a value into the calculator. The result in square millimeters 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 Millimeter to Chō converter for the reverse direction.
Step-by-step: convert chōs to square millimeters
- Write down the value in chōs (chō).
- Multiply that value by the factor 9.91736e+9.
- The product is the equivalent value in square millimeters (mm²).
- To reverse, multiply the square millimeter value by 1.008333e-10.
Worked examples
Example 1 — Convert 1 chō to mm²:
1 × 9.91736e+9 = 9.91736e+9 mm²
Example 2 — Convert 100 chō to mm²:
100 × 9.91736e+9 = 9.91736e+11 mm²
Real-world example — Geographic to fiber-optic scale
One chō equals one billion square millimeters. This conversion appears in fiber-optic specifications, where total link length is given in chōs but signal attenuation depends on micro-scale variations along the fiber.
1 chō × 9.91736e+9 = 9.91736e+9 mm²
Real-world example — Long-haul to feature-scale
One chō equals one billion square millimeters — useful in fiber-optic engineering, where total cable length is given in the larger unit but feature-level attenuation depends on micro-scale variations.
1 chō × 9.91736e+9 = 9.91736e+9 mm²
Chō to Square Millimeter conversion table
Standard reference values for converting chōs to square millimeters:
| Chō [chō] | Square Millimeter [mm²] |
|---|---|
| 0.01 | 9.91736e+7 |
| 0.1 | 9.91736e+8 |
| 1 | 9.91736e+9 |
| 2 | 1.983472e+10 |
| 3 | 2.975208e+10 |
| 4 | 3.966944e+10 |
| 5 | 4.95868e+10 |
| 10 | 9.91736e+10 |
| 20 | 1.983472e+11 |
| 30 | 2.975208e+11 |
| 40 | 3.966944e+11 |
| 50 | 4.95868e+11 |
| 100 | 9.91736e+11 |
| 500 | 4.95868e+12 |
| 1000 | 9.91736e+12 |
Frequently asked questions
How many square millimeters is 1 chō?
How do I convert chōs to square millimeters?
How do I convert square millimeters back to chōs?
How many square millimeters is 100 chōs?
Popular area unit conversions
Convert Chō to other area units
Show all Chō conversions
Metric / SI (5 units)
Imperial / US Customary (3 units)
Sources & references
Conversion factor (1 chō = 9.91736e+9 mm²) 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.