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) = 1.697885e-13 Astronomical Unit (AU).
| Inch (in) | Astronomical Unit (AU) |
|---|---|
| 0.1 | 1.697885e-14 |
| 0.5 | 8.489426e-14 |
| 1 | 1.697885e-13 |
| 2 | 3.395770e-13 |
| 5 | 8.489426e-13 |
| 10 | 1.697885e-12 |
| 25 | 4.244713e-12 |
| 50 | 8.489426e-12 |
| 100 | 1.697885e-11 |
| 500 | 8.489426e-11 |
| 1000 | 1.697885e-10 |
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 astronomical unit is a unit of length approximating the mean Earth-Sun distance, defined as exactly 149,597,870,700 meters.
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
Spacecraft mission planning, expressing planetary orbit sizes, and solar system scale models.
Light takes about 8 minutes and 20 seconds to travel 1 AU. Mars is about 1.52 AU from the Sun, Jupiter about 5.2 AU.
Thinking the AU is the exact Earth-Sun distance — Earth's actual distance varies from ~147 to ~152 Gm over the year due to orbital eccentricity.
AU makes the solar system manageable: Mercury ≈ 0.39 AU, Venus ≈ 0.72, Earth = 1, Mars ≈ 1.52, Jupiter ≈ 5.2, Saturn ≈ 9.5.



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