An inch is exactly 0.0254 meters.
Inches to Astronomical units Converter — in to AU
Convert Inch (in) to Astronomical unit (AU) using the exact conversion factor (1 inch = 1.697885e-13 astronomical unit). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Inches to Astronomical units converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
An astronomical unit is the mean Earth-Sun distance.
Result = input x 0.0254 / 1.49597871e+11.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Inches to Astronomical units
Inch and Astronomical unit both measure length. Inch is typically associated with united States and United Kingdom (small measurements, screen sizes, hardware), while Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances..
Formula
astronomical units = inches × 1.697885e-13
This factor comes from each unit's defined relationship to the category's base unit: 1 inch equals 0.0254 base units, and 1 astronomical unit equals 149597870700 base units, so dividing one by the other gives the direct inch-to-astronomical unit factor of 1.697885e-13.
Simple example
1 in × 1.697885e-13 = 1.697885e-13 AU
1 inch = 1.697885e-13 astronomical units.
Real-world example
10 in × 1.697885e-13 = 1.697885e-12 AU
10 inches = 1.697885e-12 astronomical units.
Conversion table
| Inch (in) | Astronomical unit (AU) |
|---|---|
| 1 in | 1.697885e-13 AU |
| 5 in | 8.489426e-13 AU |
| 10 in | 1.697885e-12 AU |
| 21.0975 in | 3.582113e-12 AU |
| 42.195 in | 7.164226e-12 AU |
| 100 in | 1.697885e-11 AU |
Reverse conversion: Astronomical unit to Inch
1.697885e-13 AU × 5.88968e+12 = 0.999999924 in
1.697885e-13 astronomical units = 0.999999924 inches.
inches = astronomical units × 5.88968e+12
For a page dedicated to this direction, see Astronomical unit to Inch.
Inch vs. Astronomical unit
| Aspect | Inch | Astronomical unit |
|---|---|---|
| Family | US/imperial customary unit | Non-SI unit accepted for use with SI (astronomical) |
| Typical use | Screen and display size measurement worldwide (even in metric countries) | Measuring distances within the solar system (planetary orbits) |
| Where it's used | United States and United Kingdom (small measurements, screen sizes, hardware) | Used internationally in astronomy for solar-system-scale distances. |
Understanding the Inch
Inch (in) measures distance. The international inch is defined as exactly 25.4 millimeters. It is classified as a US/imperial customary unit.
Where it's used: United States and United Kingdom (small measurements, screen sizes, hardware)
Uses of the Inch today
- Screen and display size measurement worldwide (even in metric countries)
- US/UK small-object and body measurement
- Hardware, tools, and pipe fittings (US)
History of the Inch
The inch traces to medieval England, traditionally defined as the length of three barleycorns, later standardized as 1/12 of a foot. The international inch (exactly 25.4 mm) was fixed by the same 1959 agreement that standardized the foot and yard.
Historical origin. Inch was not the invention of a single named person; it developed through the process described above.
Understanding the Astronomical unit
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Where it's used: Used internationally in astronomy for solar-system-scale distances.
Uses of the Astronomical unit today
- Measuring distances within the solar system (planetary orbits)
- Astronomical calculations and spacecraft navigation
- Popular science communication about the solar system
History of the Astronomical unit
The astronomical unit originated from 17th-19th century attempts to measure the Earth-Sun distance, refined over time using transits of Venus and later radar and spacecraft ranging.
In 2012, the International Astronomical Union fixed the AU at exactly 149,597,870,700 meters, replacing its earlier definition (tied to gravitational calculations) with a simple fixed distance, independent of the slightly-variable actual Earth-Sun distance.
Historical origin. Astronomical unit was not the invention of a single named person; it developed through the process described above.
Inch — sources
- NIST — International yard and pound (1959) — Fixes the modern inch at exactly 25.4 millimeters.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many astronomical units are in 1 inch?
1 inch equals 1.697885e-13 astronomical units, using the exact defined conversion factor rather than an estimate.
How do I convert inch to astronomical unit?
Multiply the inch value by 1.697885e-13. The converter above does this instantly to whatever precision you set.
How do I convert astronomical unit back to inch?
Use the reverse factor: 1 astronomical unit equals 5.88968e+12 inches. You can also use the swap control in the converter above to flip the direction instantly.
What is a inch?
Inch (in) measures distance. The international inch is defined as exactly 25.4 millimeters. It is classified as a US/imperial customary unit.
What is a astronomical unit?
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Is the inch to astronomical unit conversion exact?
Yes. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the inch still used today?
United States and United Kingdom (small measurements, screen sizes, hardware)