This page converts parsecs into decimeters using the factor 3.085677581e+17, and shows the reverse figure alongside it. Both units measure length, which is why one number does the whole job.
One tenth of a metre; rare in daily use but common in fluid and timber specifications. 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". The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in decimeters, so you can sanity-check whether your answer is a plausible size.
The formula
parsecs- The amount you are converting, in parsecs
3.08567758149e+17- The exact number of decimeters in one parsec
decimeters- The converted result
How it works, step by step
- Enter the value in parsecs.
- It is multiplied by 3.08567758149e+17, the exact factor between the two units.
- The answer is shown in decimeters, 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 decimeters
At 100 pc (a larger figure), the same quantity in decimeters is 100 × 3.08568e+17 = 3.08568e+19 dm. One parsec is 3.08568e+17 decimeters, so the numbers grow as expected.
A round figure: 1 pc in decimeters
Take a round figure, roughly 1 pc. The conversion is a single multiplication — 1 × 3.08568e+17 — giving 3.08568e+17 dm. Because the relationship is proportional, doubling the input doubles the answer to 6.17136e+17 dm.
How to read your score
Frequently asked questions
How many decimeters are in one parsec?
Exactly 3.08567758149e+17. 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 decimeters?
decimeters = parsecs × 3.08567758149e+17. Reversed, parsecs = decimeters ÷ 3.08567758149e+17, which is the same as multiplying by 3.24077928944e-18.
Which is the bigger unit, the parsec or the decimeter?
The parsec. One parsec equals 3.08568e+17 decimeters.
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 decimeter?
One tenth of a metre; rare in daily use but common in fluid and timber specifications.
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 dm in my head?
Plenty of people do this in their head: multiply by 3.0000e+17 instead of using the exact factor 3.0857e+17. At 100 that shortcut gives 3.0000e+19 decimeters, off by 8.5678e+17 decimeters or about 2.78%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Parsecs to decimeters reference tables
| Parsecs | Decimeters |
|---|---|
| 0.5 pc | 1.54284e+17 dm |
| 1 pc | 3.08568e+17 dm |
| 2 pc | 6.17136e+17 dm |
| 3 pc | 9.25703e+17 dm |
| 5 pc | 1.54284e+18 dm |
| 10 pc | 3.08568e+18 dm |
| 20 pc | 6.17136e+18 dm |
| 25 pc | 7.71419e+18 dm |
| 50 pc | 1.54284e+19 dm |
| 75 pc | 2.31426e+19 dm |
| 100 pc | 3.08568e+19 dm |
| 250 pc | 7.71419e+19 dm |
| 500 pc | 1.54284e+20 dm |
| 1000 pc | 3.08568e+20 dm |
| 5000 pc | 1.54284e+21 dm |
Exact factor: 1 parsec = 3.08567758149e+17 decimeters.
| Quantity | pc | dm |
|---|---|---|
| A credit card’s long edge | 2.774e-18 pc | 0.856 dm |
| A door height | 6.585e-17 pc | 20.32 dm |
| An Olympic pool | 1.620e-15 pc | 500 dm |
| The Eiffel Tower | 1.069e-14 pc | 3300 dm |
| A marathon | 1.367e-12 pc | 4.22e+05 dm |
| Earth’s diameter | 4.129e-10 pc | 1.274e+08 dm |
Published reference values, converted with the same factor this page uses.