This page converts microns into chains using the factor 4.970969538e-08, and shows the reverse figure alongside it. Both units measure length, which is why one number does the whole job.
The older name for a micrometre, still standard in filtration, machining and paint-thickness specifications. Sixty-six feet — the length of a cricket pitch, and the unit the US Public Land Survey was laid out in.
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 chains, so you can sanity-check whether your answer is a plausible size.
The formula
microns- The amount you are converting, in microns
4.9709695379e-08- The exact number of chains in one micron
chains- The converted result
How it works, step by step
- Enter the value in microns.
- It is multiplied by 4.9709695379e-08, the exact factor between the two units.
- The answer is shown in chains, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A credit card’s long edge: 8.56e+04 micron in chains
A credit card’s long edge comes to about 8.56e+04 micron. Multiplying by the factor: 8.56e+04 × 4.97097e-08 = 0.00425515 ch. Dividing the answer back by 4.97097e-08 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A door height: 2.03e+06 micron in chains
A door height comes to about 2.03e+06 micron. Multiplying by the factor: 2.03e+06 × 4.97097e-08 = 0.100911 ch. Dividing the answer back by 4.97097e-08 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 chains are in one micron?
Exactly 4.9709695379e-08. 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 microns to chains?
chains = microns × 4.9709695379e-08. Reversed, microns = chains ÷ 4.9709695379e-08, which is the same as multiplying by 20,116,800.
Which is the bigger unit, the micron or the chain?
The chain. One micron is only 4.97097e-08 of a chain, so it takes 2.01168e+07 microns to make one chain.
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 micron?
The older name for a micrometre, still standard in filtration, machining and paint-thickness specifications.
What is a chain?
Sixty-six feet — the length of a cricket pitch, and the unit the US Public Land Survey was laid out in.
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 micron to ch in my head?
Plenty of people do this in their head: divide by 20000000.000000 instead of using the exact factor 4.9710e-08. At 100 that shortcut gives 0.000005 chains, off by 2.9030e-08 chains or about 0.58%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Microns to chains reference tables
| Microns | Chains |
|---|---|
| 0.5 micron | 2.48548e-08 ch |
| 1 micron | 4.97097e-08 ch |
| 2 micron | 9.94194e-08 ch |
| 3 micron | 1.49129e-07 ch |
| 5 micron | 2.48548e-07 ch |
| 10 micron | 4.97097e-07 ch |
| 20 micron | 9.94194e-07 ch |
| 25 micron | 1.24274e-06 ch |
| 50 micron | 2.48548e-06 ch |
| 75 micron | 3.72823e-06 ch |
| 100 micron | 4.97097e-06 ch |
| 250 micron | 1.24274e-05 ch |
| 500 micron | 2.48548e-05 ch |
| 1000 micron | 4.97097e-05 ch |
| 5000 micron | 0.000248548 ch |
Exact factor: 1 micron = 4.9709695379e-08 chains.
| Quantity | micron | ch |
|---|---|---|
| A credit card’s long edge | 8.56e+04 micron | 0.004255 ch |
| A door height | 2.032e+06 micron | 0.101 ch |
| An Olympic pool | 5e+07 micron | 2.485 ch |
| The Eiffel Tower | 3.3e+08 micron | 16.4 ch |
| A marathon | 4.22e+10 micron | 2098 ch |
| Earth’s diameter | 1.274e+13 micron | 6.334e+05 ch |
Published reference values, converted with the same factor this page uses.