Convert Millimeter to Sun's Radius
Convert millimeters to sun's radii instantly. 1 millimeter = 1.437401e-12 sun's radius — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Sun's Radius to Millimeter converter for the reverse conversion.
Units explained
Millimeter
A millimeter is a metric unit of length equal to one thousandth of a meter (1/1000 m). It is the standard small-scale unit in the SI system and is widely used wherever sub-centimeter precision matters.
The millimeter was defined alongside the meter when France adopted the metric system in 1795, using the standard SI prefix milli- (from Latin mille, "thousand") to denote one-thousandth.
Millimeters are used in engineering drawings, machining, manufacturing, paper sizes, rainfall measurement, and any context where dimensions below one centimeter need to be specified clearly. Most rulers worldwide are marked in millimeters.
Adopted in 1795 in France as part of the original metric system; standardized internationally by the Metre Convention in 1875 and confirmed in the SI in 1960.
Sun's Radius
The Sun's radius is approximately 695,700 km (6.957×10⁸ m), defined as the IAU 2015 nominal solar radius for use in stellar physics and exoplanet research.
The IAU (International Astronomical Union) Resolution B3 in 2015 defined a nominal solar radius of exactly 6.957×10⁸ m to serve as a stable reference, independent of actual measurement-uncertainty variations in the real Sun.
Solar radii are used in stellar physics, exoplanet characterisation, and any context where a star's size is expressed relative to the Sun. Most stellar radius measurements are quoted in solar-radius units rather than meters.
Defined exactly at 6.957×10⁸ m by IAU Resolution B3 in 2015.
Millimeter to Sun's Radius conversion formula
The relationship between millimeters and sun's radii:
To convert millimeters to sun's radii, multiply the value in millimeters by 1.437401e-12. To reverse, multiply sun's radii by 6.957e+11.
How to use this converter
Type a value into the calculator. The result in sun's radii updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Sun's Radius to Millimeter converter for the reverse direction.
Step-by-step: convert millimeters to sun's radii
- Write down the value in millimeters (mm).
- Multiply that value by the factor 1.437401e-12.
- The product is the equivalent value in sun's radii (R☉).
- To reverse, multiply the sun's radius value by 6.957e+11.
Worked examples
Example 1 — Convert 1 mm to R☉:
1 × 1.437401e-12 = 1.437401e-12 R☉
Example 2 — Convert 100 mm to R☉:
100 × 1.437401e-12 = 1.437401e-10 R☉
Real-world example — Postcard and small-object dimensions
A postcard is about 5 millimeters wide. Converting to sun's radii is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 mm × 1.437401e-12 = 7.187006e-12 R☉
Real-world example — Ruler-scale measurements
A 30-millimeter school ruler converts cleanly to sun's radii — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 mm × 1.437401e-12 = 4.312204e-11 R☉
Real-world example — Hardware-scale dimensions
A 10-millimeter fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between millimeters and sun's radii daily when mixing metric and imperial tools.
10 mm × 1.437401e-12 = 1.437401e-11 R☉
Millimeter to Sun's Radius conversion table
Standard reference values for converting millimeters to sun's radii:
| Millimeter [mm] | Sun's Radius [R☉] |
|---|---|
| 0.01 | 1.437401e-14 |
| 0.1 | 1.437401e-13 |
| 1 | 1.437401e-12 |
| 2 | 2.874802e-12 |
| 3 | 4.312204e-12 |
| 4 | 5.749605e-12 |
| 5 | 7.187006e-12 |
| 10 | 1.437401e-11 |
| 20 | 2.874802e-11 |
| 30 | 4.312204e-11 |
| 40 | 5.749605e-11 |
| 50 | 7.187006e-11 |
| 100 | 1.437401e-10 |
| 500 | 7.187006e-10 |
| 1000 | 1.437401e-9 |
Frequently asked questions
How many sun's radii is 1 millimeter?
How do I convert millimeters to sun's radii?
How do I convert sun's radii back to millimeters?
How many sun's radii is 100 millimeters?
Popular length unit conversions
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Metric / SI (17 units)
Imperial / US Customary (27 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 mm = 1.437401e-12 R☉) 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.