To convert parsecs to nanometers, multiply by 3.085677581e+25. That factor is the whole relationship: both units measure length, so the conversion is a proportion with no offset and no substance-specific constant.
One billionth of a metre — the scale of light wavelengths and chip lithography. 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". Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into nanometers, which is usually more useful than the bare number.
The formula
parsecs- The amount you are converting, in parsecs
3.08567758149e+25- The exact number of nanometers in one parsec
nanometers- The converted result
How it works, step by step
- Enter the value in parsecs.
- It is multiplied by 3.08567758149e+25, the exact factor between the two units.
- The answer is shown in nanometers, 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 nanometers
Take a larger figure, roughly 100 pc. The conversion is a single multiplication — 100 × 3.08568e+25 — giving 3.08568e+27 nm. Because the relationship is proportional, doubling the input doubles the answer to 6.17136e+27 nm.
A round figure: 1 pc in nanometers
A round figure comes to about 1 pc. Multiplying by the factor: 1 × 3.08568e+25 = 3.08568e+25 nm. Dividing the answer back by 3.08568e+25 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 nanometers are in one parsec?
Exactly 3.08567758149e+25. 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 nanometers?
nanometers = parsecs × 3.08567758149e+25. Reversed, parsecs = nanometers ÷ 3.08567758149e+25, which is the same as multiplying by 3.24077928944e-26.
Which is the bigger unit, the parsec or the nanometer?
The parsec. One parsec equals 3.08568e+25 nanometers.
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 nanometer?
One billionth of a metre — the scale of light wavelengths and chip lithography.
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 nm in my head?
Plenty of people do this in their head: multiply by 3.0000e+25 instead of using the exact factor 3.0857e+25. At 100 that shortcut gives 3.0000e+27 nanometers, off by 8.5678e+25 nanometers or about 2.78%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Parsecs to nanometers reference tables
| Parsecs | Nanometers |
|---|---|
| 0.5 pc | 1.54284e+25 nm |
| 1 pc | 3.08568e+25 nm |
| 2 pc | 6.17136e+25 nm |
| 3 pc | 9.25703e+25 nm |
| 5 pc | 1.54284e+26 nm |
| 10 pc | 3.08568e+26 nm |
| 20 pc | 6.17136e+26 nm |
| 25 pc | 7.71419e+26 nm |
| 50 pc | 1.54284e+27 nm |
| 75 pc | 2.31426e+27 nm |
| 100 pc | 3.08568e+27 nm |
| 250 pc | 7.71419e+27 nm |
| 500 pc | 1.54284e+28 nm |
| 1000 pc | 3.08568e+28 nm |
| 5000 pc | 1.54284e+29 nm |
Exact factor: 1 parsec = 3.08567758149e+25 nanometers.
| Quantity | pc | nm |
|---|---|---|
| A credit card’s long edge | 2.774e-18 pc | 8.56e+07 nm |
| A door height | 6.585e-17 pc | 2.032e+09 nm |
| An Olympic pool | 1.620e-15 pc | 5e+10 nm |
| The Eiffel Tower | 1.069e-14 pc | 3.3e+11 nm |
| A marathon | 1.367e-12 pc | 4.22e+13 nm |
| Earth’s diameter | 4.129e-10 pc | 1.274e+16 nm |
Published reference values, converted with the same factor this page uses.