Convert nm to m nanometres ↔ metres Free Online Secure
Type a value in nanometres and read it in metres at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert nm to m (nanometres ↔ metres)
| nm | m |
|---|---|
| 1 | 0.000000001 |
| 2 | 0.000000002 |
| 3 | 0.000000003 |
| 5 | 0.000000005 |
| 10 | 0.00000001 |
| 20 | 0.00000002 |
| 50 | 0.00000005 |
| 100 | 0.0000001 |
Where these units come from
The metre was first defined in 1793 as a ten-millionth of the distance from the equator to the North Pole — a definition nobody could check without surveying a quarter of the planet. It has been redefined four times since, each time to something steadier: a platinum bar, then a prototype kept in Paris, then a wavelength of krypton light, and since 1983 the distance light travels in vacuum in 1/299,792,458 of a second. The inch stopped being a separate thing in 1959, when six countries agreed to define it as exactly 25.4 mm. That agreement is why every conversion on this page between a metric and an imperial length is exact rather than measured: both sides now descend from the same definition.
Where you meet them
Millimetres are the working unit of engineering drawings and of anything made in a workshop; centimetres belong to tailoring, furniture and school rulers; metres to rooms, fabric and running tracks. Feet and inches survive in aviation altitudes worldwide, in American and British construction, and in the diagonal of every screen you have ever bought. Nautical miles are not a quaint survival — one is a minute of latitude, which is why ships and aircraft still navigate in them.
Questions people ask
How small is a nanometre?
A nanometre is a billionth of a metre. Visible light has wavelengths of roughly 400 to 700 nanometres, and a human hair is about 80,000 nanometres across. You meet the unit wherever things are too small to see: wavelengths of light, the thickness of coatings, the size of viruses and the features of microchips.
How is the metre defined today?
As the distance light travels in a vacuum in 1/299,792,458 of a second. The definition has been in place since 1983 and ties the metre to the speed of light, which is itself fixed at exactly 299,792,458 metres per second. The old platinum bar in Paris no longer defines anything.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Putting a wavelength into the equation: how to convert nm to m
Physics formulas are written for metres, but light, atoms and molecules are measured in nanometres. A student told that green light has a wavelength of 550 nm cannot put that straight into the formula for frequency or photon energy; the 550 must become 0.00000055 m, or 5.5 times ten to the minus seven. Every optics course, every spectroscopy lab and every datasheet for a laser or an LED asks for the same move. To make it, you convert nm to m, and this page does it as you type, showing the result in full and in scientific notation.
The rule is a division by one billion, which moves the decimal point nine places to the left. It is exact, but the result has many zeros, which is why scientific notation is the clearest way to write it. The sections below give the rule with examples, portraits of both units, a comparison, the places where the conversion is needed and the mistakes to avoid.
How to convert nm to m: divide by 1,000,000,000
The rule
One nanometre is one billionth of a metre, 10 to the minus ninth. To convert nm to m, divide the number of nanometres by one billion, or move the decimal point nine places to the left. 1 nm is 1e-9 m, 550 nm is 5.5e-7 m, 0.3 nm is 3e-10 m and 1,000,000,000 nm is 1 m. In the other direction, multiply by one billion.
Examples
Green light of 550 nm is 5.5e-7 m. Red light of 700 nm is 7e-7 m. An ultraviolet line of 254 nm is 2.54e-7 m. A virus of 100 nm is 1e-7 m. A water molecule of 0.3 nm is 3e-10 m. A hydrogen atom of 0.1 nm is 1e-10 m.
Counting in thousands
For a mental convert nm to m, go in steps of three: nanometre to micrometre is three places, micrometre to millimetre three more, millimetre to metre three more. 550 nm is 0.55 µm, then 0.00055 mm, then 0.00000055 m. Each step is a division by a thousand, and the three together give the billion.
Scientific notation
Write the answer as a number between 1 and 10 times a power of ten. 550 nm becomes 5.5 times ten to the minus 7. The exponent is the number of places the point has moved, with a minus sign for a small number. Enter such values in a calculator with the E key: 5.5E-7.
The nanometre
A billionth of a metre
The nanometre is a billionth of a metre. The prefix nano is from the Greek for dwarf. The unit is used for wavelengths of light, for the sizes of molecules and viruses and for the features of microchips. The symbol is nm.
The ladder below the micrometre
A nanometre is a thousandth of a micrometre and a thousand times a picometre. Atoms are about 0.1 nm, which is 100 picometres. The ångström, an older unit of 0.1 nm, still appears in chemistry and crystallography.
The metre
The base unit
The metre is the SI base unit of length, defined from the speed of light. Physical formulas are written in SI units, so a wavelength must be in metres to give a frequency in hertz or an energy in joules.
The base of formulas
The speed of light, 299,792,458 m/s, Planck's constant, 6.626e-34 J s, and the Rydberg constant all use metres. That is why the conversion is the first step in many calculations.
Nanometre and metre compared
A metre is a billion nanometres. The conversion from nanometres to metres produces numbers with many zeros, and scientists write them in powers of ten. A wavelength of 550 nm is 5.5e-7 m; a range of 380 to 750 nm is 3.8e-7 to 7.5e-7 m.
When you present results, keep nanometres where the numbers are readable and metres in formulas. Do not mix the two in a calculation without conversion; a factor of a billion is easy to miss.
Where you will need it
Frequency of light
Frequency equals the speed of light divided by the wavelength. For 550 nm, convert to 5.5e-7 m, then divide 3e8 by 5.5e-7 to get 5.45e14 hertz. If you forget to convert and use 550, the answer is a billion times too small. Red light of 700 nm has a frequency of 4.3e14 Hz, violet of 400 nm 7.5e14 Hz.
Photon energy
The energy of a photon is Planck's constant times frequency, or hc divided by wavelength. For 550 nm, 5.5e-7 m: 6.626e-34 times 3e8 divided by 5.5e-7 gives 3.6e-19 joules, 2.25 electronvolts. The calculation needs the “convert nm to m” calculation step first.
Diffraction and gratings
A grating with 600 lines per millimetre has a spacing of 1,667 nm, 1.667e-6 m. For light of 550 nm the first-order angle is the arcsine of 550 divided by 1,667, which is 19.3 degrees. The formula requires both in the same unit; nanometres will do if the spacing is also in nanometres.
Radio and microwaves
Longer waves are in metres: an FM station at 100 MHz has a wavelength of 3 m, 3e9 nm. A mobile phone at 2.4 GHz has 12.5 cm, 1.25e8 nm. The same electromagnetic spectrum covers 15 orders of magnitude, from gamma rays at 1e-3 nm to long radio waves of thousands of metres.
The electromagnetic spectrum
From X-rays to radio
X-rays have wavelengths of 0.01 to 10 nm, 1e-11 to 1e-8 m. Ultraviolet is 10 to 400 nm. Visible light is 380 to 750 nm. Infrared is 750 nm to 1 mm, 1e-3 m. Microwaves are 1 mm to 1 m. Radio is longer than 1 m. Placing each band in metres gives a single scale.
A table for reference
Hard X-ray 0.1 nm, 1e-10 m; soft X-ray 5 nm, 5e-9 m; UV-C 254 nm, 2.54e-7 m; green 550 nm, 5.5e-7 m; near infrared 1,000 nm, 1e-6 m; thermal infrared 10,000 nm, 1e-5 m.
A worked example
Which colour is a laser?
A laser has a wavelength of 532 nm. To convert nm to m, divide by 1e9: 5.32e-7 m. The frequency is 3e8 divided by 5.32e-7, which is 5.64e14 Hz. The photon energy is 2.33 eV. A laser pointer of this wavelength is green. A quick comparison with the spectrum table above confirms it.
Check
Multiply 5.32e-7 by 1e9 and you return to 532. If you get 5.32e2, that is the same number in exponent form.
Final checks
Round trip
Multiply your answer by one billion. If you return to the nanometres you started with, the conversion is right. If you land at 1e6 or 1e12 times off, check the exponent.
Notes
Write both figures and the exponent in your notes. A later reader can then follow your steps.
Lasers in medicine and industry
Wavelengths and their jobs
A diode laser for hair removal works at 810 nm, 8.1e-7 m. An Nd:YAG surgical laser emits at 1,064 nm, 1.064e-6 m. A carbon dioxide cutting laser uses 10,600 nm, 1.06e-5 m. An excimer laser for eye surgery works at 193 nm, 1.93e-7 m. Each wavelength is absorbed by a different tissue or material, so the nanometre figure on the label decides what the device does. Engineers checking the optics must convert nm to m before they apply a formula.
Safety goggles
Goggles are rated for a range of wavelengths, such as 800 to 1,100 nm. A pair for an 810 nm laser is no good for a 193 nm one. Always check the range in the same unit as the laser.
Sunlight and solar cells
The solar spectrum
Sunlight peaks at about 500 nm, 5e-7 m, and spreads from 300 to 2,500 nm. A silicon cell absorbs up to 1,100 nm, 1.1e-6 m, the band gap of 1.12 eV. Light beyond that passes through; shorter wavelengths give more energy than the cell can use, and the surplus becomes heat. That is why efficiency is limited to about 30 per cent for a single junction.
Calculating the cut-off
Wavelength equals 1,240 divided by the band gap in electron volts, giving nanometres: 1,240 divided by 1.12 is 1,107 nm. To use the result in a formula with c and Planck's constant, convert it to metres: 1.107e-6 m.
Spectrometers and calibration
Reading a spectrum
A spectrometer plots intensity against wavelength in nanometres. Calibration lamps have known lines: mercury at 253.7, 365.0, 404.7, 435.8, 546.1 and 577.0 nm; neon at 585.2 and 640.2 nm. A student fitting the scale to these lines learns that the instrument error is typically less than 1 nm, 1e-9 m.
Resolution
A spectrometer with a resolution of 0.1 nm can tell the two sodium lines at 589.0 and 589.6 nm apart. In metres, the difference is 6e-10 m. The tiny number shows why spectroscopists prefer nanometres.
Astronomy: redshift and starlight
Shifted wavelengths
The hydrogen alpha line at 656.3 nm, 6.563e-7 m, is shifted to longer wavelengths in the light of receding galaxies. A redshift of 0.1 moves it to 722 nm, 7.22e-7 m. Astronomers compute the redshift as the change in wavelength divided by the rest wavelength, a ratio that is the same in any unit but must use a common unit for both numbers. To find the speed of the galaxy, multiply the redshift by the speed of light in metres per second after a “convert nm to m” calculation for the lines.
Why the nanometre
Spectra of stars cover thousands of lines, each known to a fraction of a nanometre. In metres, the list would be a block of numbers with eight or nine zeros after the decimal point. In nanometres, they are three-digit figures that can be scanned in a catalogue.
Atoms and molecules in metres
Atomic scale
A hydrogen atom has a Bohr radius of 0.0529 nm, 5.29e-11 m. A carbon atom is about 0.17 nm in diameter, 1.7e-10 m. The distance between carbon atoms in graphene is 0.142 nm, 1.42e-10 m, and a single sheet of graphene is 0.335 nm thick, 3.35e-10 m.
Biological molecules
DNA is 2 nm wide, 2e-9 m. A protein such as haemoglobin is 5.5 nm. A ribosome is 25 nm. A lipid bilayer is 5 nm thick. These sizes sit between atoms and cells.
Microchips and thin films
Feature sizes
A gate length of 20 nm is 2e-8 m. A modern fin is 7 nm wide, 7e-9 m. A metal line in a processor may be 20 nm. The oxide insulating the gate is about 1 nm thick, 1e-9 m, only a few atoms. Process names such as 3 nm are marketing labels, not exact lengths.
Thin films
An anti-reflection coating is about 100 nm, 1e-7 m. A soap bubble wall is 300 nm. The wavelengths of reflected colour depend on the thickness, so engineers convert to metres to apply interference formulas.
Quantum and atomic physics
De Broglie wavelength
An electron accelerated through 100 volts has a wavelength of 0.123 nm, 1.23e-10 m, close to the spacing of atoms in a crystal. That is why electrons diffract from crystals and why electron microscopes can resolve atoms. The calculation is in metres, but the result is quoted in nanometres.
Spectral lines
Hydrogen has lines at 656.3, 486.1, 434.0 and 410.2 nm, 6.563e-7, 4.861e-7, 4.340e-7 and 4.102e-7 m. The Rydberg formula uses metres. Students check that the calculated wavelengths match the observed values.
Spreadsheet formulas
Formula
To convert nm to m for a column, put nanometres in column A and enter =A2/1E9 in column B. Format in scientific notation with three decimals. To reverse, multiply by 1E9. If you only need the exponent form, use the scientific number format.
Check values
Enter 1: result 1E-09. Enter 550: 5.50E-07. Enter 1000000000: 1. If you see 0.00000055 and want the exponent, change the cell format.
Rounding and significant figures
Match the data
A wavelength of 550 nm has two or three significant figures. Its value in metres is 5.5e-7 or 5.50e-7. Do not write 5.5000e-7, which suggests a precision that the data lacks. Laser wavelengths are known more precisely: 632.8 nm, 6.328e-7 m.
Propagation
When you use the converted wavelength in a formula, the result has the same number of significant figures. A frequency from 550 nm is 5.5e14 Hz, not 5.4545e14.
Teaching the exponent
Three steps down
To teach the “convert nm to m” calculation, draw a ladder: metre, millimetre (1e-3), micrometre (1e-6), nanometre (1e-9). To go from nanometres to metres you climb three rungs, dividing by a thousand each time. Students see that the exponent is simply minus three, minus six, minus nine.
A drill
Give students ten wavelengths in nanometres and ask for metres in scientific notation. Check with this page. The most common error is writing 5.5e7 instead of 5.5e-7.
History of the unit
From the ångström
Before nanometres, spectroscopists used the ångström, 1e-10 m, named after Anders Ångström who measured the solar spectrum in 1868. The nanometre replaced it in the SI era because it fits the prefix system. A wavelength of 5,500 Å is 550 nm.
The prefix nano
Nano was adopted by the CGPM in 1960. Since then it has become the favourite prefix of technology.
Language and symbols
Symbols
The symbol is nm, lower case, no plural. The exponent form, 1e-9 or 10 to the minus 9, is used in formulas. In plain text, write 5.5e-7 m or 5.5 x 10^-7 m.
Words
Nano from the Greek nanos, a dwarf. The word is also used for a billionth of a second, nanosecond, a billionth of a gram, nanogram, and so on.
More values for convert nm to m
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 nm = 0.0000000001 m
- 0.5 nm = 0.0000000005 m
- 3 nm = 0.000000003 m
- 4 nm = 0.000000004 m
- 7 nm = 0.000000007 m
- 15 nm = 0.000000015 m
- 20 nm = 0.00000002 m
- 75 nm = 0.000000075 m
- 200 nm = 0.0000002 m
- 500 nm = 0.0000005 m
- 2,000 nm = 0.000002 m
- 10,000 nm = 0.00001 m
Mistakes when you convert nm to m
Wrong sign on the exponent
5.5e7 is 55 million, not a wavelength. Small numbers have a negative exponent.
Six places instead of nine
That gives micrometres. For metres, nine places.
Multiplying instead of dividing
The metre is the larger unit, so the number gets smaller. If 550 nm becomes 5.5e11, you multiplied.
Quick answers
How many metres in a nanometre?
One billionth, 1e-9.
How do I convert nm to m?
Divide by 1,000,000,000.
What is 550 nm in metres?
5.5e-7 m.
Is the conversion exact?
Yes, exact.
Does my number leave my device?
No. The calculation runs in your browser.
Related pages and a last word
If you work with lengths, these conversions are close at hand: Convert km to m, Convert mm to m, Convert m to cm, Convert °C to °F, Convert °F to °C, Convert L to gal, Convert gal to L, Convert acres to mi², Convert °F to K. The reverse of this page is Convert m to nm.
In short, to convert nm to m divide by a billion, write the answer in scientific notation and keep only the digits your measurement supports. Your number stays on your device: nothing is uploaded and no account is needed.