This page converts parsecs into astronomical units using the factor 206,264.8062, and shows the reverse figure alongside it. Both units measure length, which is why one number does the whole job.
Exactly 149,597,870,700 metres — the Earth–Sun distance, and the natural ruler for the solar system. The distance at which one astronomical unit subtends one arcsecond: about 3.26 light-years.
The mil and the millimetre are not the same thing and are out by a factor of about forty. A mil is one thousandth of an inch — 0.0254 mm — and a spec sheet that quotes film thickness in mils means the small unit. British drawings write the same size as "thou". Below the calculator there is a step table for the values people look up most, and a second table putting real length figures into astronomical units so the number you get has something to be compared against.
The formula
parsecs- The amount you are converting, in parsecs
206,264.806247- The exact number of astronomical units in one parsec
astronomical units- The converted result
How it works, step by step
- Enter the value in parsecs.
- It is multiplied by 206,264.806247, the exact factor between the two units.
- The answer is shown in astronomical units, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A round figure: 1 pc in astronomical units
At 1 pc (a round figure), the same quantity in astronomical units is 1 × 206,265 = 206,265 AU. One parsec is 206,265 astronomical units, so the numbers grow as expected.
A larger figure: 100 pc in astronomical units
A larger figure comes to about 100 pc. Multiplying by the factor: 100 × 206,265 = 2.06265e+07 AU. Dividing the answer back by 206,265 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many astronomical units are in one parsec?
Exactly 206,264.806247. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert parsecs to astronomical units?
astronomical units = parsecs × 206,264.806247. Reversed, parsecs = astronomical units ÷ 206,264.806247, which is the same as multiplying by 4.8481368111e-06.
Which is the bigger unit, the parsec or the astronomical unit?
The parsec. One parsec equals 206,265 astronomical units.
What does this quantity actually measure?
Both units measure length. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a parsec?
The distance at which one astronomical unit subtends one arcsecond: about 3.26 light-years.
What is a astronomical unit?
Exactly 149,597,870,700 metres — the Earth–Sun distance, and the natural ruler for the solar system.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do pc to AU in my head?
Plenty of people do this in their head: multiply by 200,000 instead of using the exact factor 206,264.8062. At 100 that shortcut gives 20,000,000 astronomical units, off by 626480.624710 astronomical units or about 3.04%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Parsecs to astronomical units reference tables
| Parsecs | Astronomical Units |
|---|---|
| 0.5 pc | 103,132 AU |
| 1 pc | 206,265 AU |
| 2 pc | 412,530 AU |
| 3 pc | 618,794 AU |
| 5 pc | 1.03132e+06 AU |
| 10 pc | 2.06265e+06 AU |
| 20 pc | 4.1253e+06 AU |
| 25 pc | 5.15662e+06 AU |
| 50 pc | 1.03132e+07 AU |
| 75 pc | 1.54699e+07 AU |
| 100 pc | 2.06265e+07 AU |
| 250 pc | 5.15662e+07 AU |
| 500 pc | 1.03132e+08 AU |
| 1000 pc | 2.06265e+08 AU |
| 5000 pc | 1.03132e+09 AU |
Exact factor: 1 parsec = 206,264.806247 astronomical units.
| Quantity | pc | AU |
|---|---|---|
| A credit card’s long edge | 2.774e-18 pc | 5.722e-13 AU |
| A door height | 6.585e-17 pc | 1.358e-11 AU |
| An Olympic pool | 1.620e-15 pc | 3.342e-10 AU |
| The Eiffel Tower | 1.069e-14 pc | 2.206e-09 AU |
| A marathon | 1.367e-12 pc | 2.821e-07 AU |
| Earth’s diameter | 4.129e-10 pc | 8.518e-05 AU |
Published reference values, converted with the same factor this page uses.