Instant · Precise · Universal
32 units available
6 categories total
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
For example, 1 Millimeter (mm) = 1.567856e-10 Earth's Equatorial Radius (R⊕ (eq)).
| Millimeter (mm) | Earth's Equatorial Radius (R⊕ (eq)) |
|---|---|
| 0.1 | 1.567856e-11 |
| 0.5 | 7.839280e-11 |
| 1 | 1.567856e-10 |
| 2 | 3.135712e-10 |
| 5 | 7.839280e-10 |
| 10 | 1.567856e-9 |
| 25 | 3.919640e-9 |
| 50 | 7.839280e-9 |
| 100 | 1.567856e-8 |
| 500 | 7.839280e-8 |
| 1000 | 1.567856e-7 |
The millimeter is a unit of length equal to one thousandth of a meter (10⁻³ m), or one tenth of a centimeter.
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
Engineering drawings, screw thread specifications, rainfall measurements, paper thickness, and small component dimensions.
Standard A4 paper is 210 × 297 mm. A credit card is about 0.76 mm thick.
Confusing mm with cm on rulers — each cm mark has 10 mm divisions. Also, misreading calipers by one mm.
A dime is about 1.3 mm thick — use it as a quick visual reference for millimeter scale.
The Earth's equatorial radius is the distance from Earth's center to the equator, approximately 6,378.137 km.
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
To convert Earth radii to meters: multiply by 6,378,137.
GPS calculations, satellite orbit determination, map projections, and geophysical modeling.
Earth is not a perfect sphere — the equatorial radius is about 21 km (0.3%) larger than the polar radius due to rotational flattening.
Using the equatorial radius as if Earth were a sphere — for precision, you must account for the oblate spheroid shape.
Earth's equatorial radius (6,378 km) vs. polar radius (6,357 km) shows the planet bulges at the equator due to spinning.



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