One picometer is exactly 1.000000000e-15 kilometers, so converting picometers 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. One trillionth of a metre, the SI unit crystallographers use where chemists still reach for angstroms.
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 kilometers, which is usually more useful than the bare number.
The formula
picometers- The amount you are converting, in picometers
1.00000000000e-15- The exact number of kilometers in one picometer
kilometers- The converted result
How it works, step by step
- Enter the value in picometers.
- It is multiplied by 1.00000000000e-15, 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 round figure: 1 pm in kilometers
At 1 pm (a round figure), the same quantity in kilometers is 1 × 1.00000e-15 = 1.00000e-15 km. One picometer is 1.00000e-15 kilometers, so the numbers shrink as expected.
A larger figure: 100 pm in kilometers
At 100 pm (a larger figure), the same quantity in kilometers is 100 × 1.00000e-15 = 1.00000e-13 km. One picometer is 1.00000e-15 kilometers, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many kilometers are in one picometer?
Exactly 1.00000000000e-15. 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 picometers to kilometers?
kilometers = picometers × 1.00000000000e-15. Reversed, picometers = kilometers ÷ 1.00000000000e-15, which is the same as multiplying by 1e+15.
Which is the bigger unit, the picometer or the kilometer?
The kilometer. One picometer is only 1.00000e-15 of a kilometer, so it takes 1e+15 picometers to make one kilometer.
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 picometer?
One trillionth of a metre, the SI unit crystallographers use where chemists still reach for angstroms.
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.
Picometers to kilometers reference tables
| Picometers | Kilometers |
|---|---|
| 0.5 pm | 5.00000e-16 km |
| 1 pm | 1.00000e-15 km |
| 2 pm | 2.00000e-15 km |
| 3 pm | 3.00000e-15 km |
| 5 pm | 5.00000e-15 km |
| 10 pm | 1.00000e-14 km |
| 20 pm | 2.00000e-14 km |
| 25 pm | 2.50000e-14 km |
| 50 pm | 5.00000e-14 km |
| 75 pm | 7.50000e-14 km |
| 100 pm | 1.00000e-13 km |
| 250 pm | 2.50000e-13 km |
| 500 pm | 5.00000e-13 km |
| 1000 pm | 1.00000e-12 km |
| 5000 pm | 5.00000e-12 km |
Exact factor: 1 picometer = 1.00000000000e-15 kilometers.
| Quantity | pm | km |
|---|---|---|
| A credit card’s long edge | 8.56e+10 pm | 8.56e-05 km |
| A door height | 2.032e+12 pm | 0.002032 km |
| An Olympic pool | 5e+13 pm | 0.05 km |
| The Eiffel Tower | 3.3e+14 pm | 0.33 km |
| A marathon | 4.220e+16 pm | 42.2 km |
| Earth’s diameter | 1.274e+19 pm | 1.274e+04 km |
Published reference values, converted with the same factor this page uses.