One parsec is exactly 3.085677581e+13 kilometers, so converting parsecs to kilometers is a single multiplication. Enter any figure and the result appears as you type — the arithmetic runs in your browser, so nothing is sent anywhere.
One thousand metres — the standard road-distance unit almost everywhere outside the US and UK. 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 kilometers so the number you get has something to be compared against.
The formula
parsecs- The amount you are converting, in parsecs
3.08567758149e+13- The exact number of kilometers in one parsec
kilometers- The converted result
How it works, step by step
- Enter the value in parsecs.
- It is multiplied by 3.08567758149e+13, the exact factor between the two units.
- The answer is shown in kilometers, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A larger figure: 100 pc in kilometers
Take a larger figure, roughly 100 pc. The conversion is a single multiplication — 100 × 3.08568e+13 — giving 3.08568e+15 km. Because the relationship is proportional, doubling the input doubles the answer to 6.17136e+15 km.
A round figure: 1 pc in kilometers
Take a round figure, roughly 1 pc. The conversion is a single multiplication — 1 × 3.08568e+13 — giving 3.08568e+13 km. Because the relationship is proportional, doubling the input doubles the answer to 6.17136e+13 km.
How to read your score
Frequently asked questions
How many kilometers are in one parsec?
Exactly 3.08567758149e+13. 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 kilometers?
kilometers = parsecs × 3.08567758149e+13. Reversed, parsecs = kilometers ÷ 3.08567758149e+13, which is the same as multiplying by 3.24077928944e-14.
Which is the bigger unit, the parsec or the kilometer?
The parsec. One parsec equals 3.08568e+13 kilometers.
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 kilometer?
One thousand metres — the standard road-distance unit almost everywhere outside the US and UK.
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 km in my head?
Plenty of people do this in their head: multiply by 3.0000e+13 instead of using the exact factor 3.0857e+13. At 100 that shortcut gives 3.0000e+15 kilometers, off by 8.5678e+13 kilometers or about 2.78%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Parsecs to kilometers reference tables
| Parsecs | Kilometers |
|---|---|
| 0.5 pc | 1.54284e+13 km |
| 1 pc | 3.08568e+13 km |
| 2 pc | 6.17136e+13 km |
| 3 pc | 9.25703e+13 km |
| 5 pc | 1.54284e+14 km |
| 10 pc | 3.08568e+14 km |
| 20 pc | 6.17136e+14 km |
| 25 pc | 7.71419e+14 km |
| 50 pc | 1.54284e+15 km |
| 75 pc | 2.31426e+15 km |
| 100 pc | 3.08568e+15 km |
| 250 pc | 7.71419e+15 km |
| 500 pc | 1.54284e+16 km |
| 1000 pc | 3.08568e+16 km |
| 5000 pc | 1.54284e+17 km |
Exact factor: 1 parsec = 3.08567758149e+13 kilometers.
| Quantity | pc | km |
|---|---|---|
| A credit card’s long edge | 2.774e-18 pc | 8.56e-05 km |
| A door height | 6.585e-17 pc | 0.002032 km |
| An Olympic pool | 1.620e-15 pc | 0.05 km |
| The Eiffel Tower | 1.069e-14 pc | 0.33 km |
| A marathon | 1.367e-12 pc | 42.2 km |
| Earth’s diameter | 4.129e-10 pc | 1.274e+04 km |
Published reference values, converted with the same factor this page uses.