Instant · Precise · Universal
32 units available
6 categories total
To convert inches to cm: multiply by 2.54. To convert cm to inches: divide by 2.54.
1 in = 25.4 mm = 2.54 cm = 1/12 ft = 1/36 yd.
For example, 1 Inch (in) = 2.540000e-20 Exameter (Em).
| Inch (in) | Exameter (Em) |
|---|---|
| 0.1 | 2.540000e-21 |
| 0.5 | 1.270000e-20 |
| 1 | 2.540000e-20 |
| 2 | 5.080000e-20 |
| 5 | 1.270000e-19 |
| 10 | 2.540000e-19 |
| 25 | 6.350000e-19 |
| 50 | 1.270000e-18 |
| 100 | 2.540000e-18 |
| 500 | 1.270000e-17 |
| 1000 | 2.540000e-17 |
The inch is a unit of length in the imperial and US customary systems, defined as exactly 25.4 millimeters.
1 in = 25.4 mm = 2.54 cm = 1/12 ft = 1/36 yd.
To convert inches to cm: multiply by 2.54. To convert cm to inches: divide by 2.54.
Screen sizes (TVs, monitors), drill bit sizes, pipe diameters, screw dimensions, and rainfall measurement in the US.
King Edward II of England defined the inch as 'three grains of barley, dry and round, placed end to end' in 1324.
Forgetting that fractions of an inch use powers of 2 (1/2, 1/4, 1/8, 1/16), not decimal subdivisions like metric.
Your thumb from tip to first knuckle is roughly 1 inch — a handy (literal) reference.
The exameter is a unit of length equal to 10¹⁸ meters, or about 105.7 light-years.
1 Em = 10¹⁸ m = 1,000 Pm ≈ 105.7 light-years ≈ 32.4 parsecs.
To convert Em to light-years: multiply by 105.7. To convert Em to parsecs: multiply by 32.4.
No practical applications. Theoretical framework for expressing galactic neighborhood distances.
The Milky Way galaxy has a diameter of about 10 Em (100,000 light-years).
Em is almost never used — astronomers use parsecs or light-years. It exists only for SI completeness.
Just remember: Exa = 10¹⁸. The Milky Way is about 10 Em across for a sense of scale.



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