Nm Converter - Convert Nanometers to Any Length or Light Unit
Use this nm converter to translate any nanometer value into meters, micrometers, picometers, ångströms, inches, and feet, plus the matching frequency (THz) and photon energy (eV).
Nm Converter
Results
550 nanometer = 550 × 1e-9 m = 5.5e-7 m
What is an nm converter?
An nm converter is a quick way to translate between nanometers and every other length unit you might need, from meters and millimeters down to picometers and ångströms, and even from light's wavelength into frequency or photon energy. It belongs wherever very small dimensions meet multiple unit systems in the same project.
A nanometer is one billionth of a meter, or 1×10⁻⁹ m. That is the scale of ultraviolet and visible light, viruses, semiconductor features, and the wavelengths used in fiber optics. Most everyday length units are too large to be useful at this scale, while picometers and ångströms are too small for routine work — so the nanometer is the practical middle ground.
This calculator works for a wide range of cases:
- Laser and light wavelength — convert a 532 nm green laser into THz (≈ 563 THz) and eV (≈ 2.33 eV) for a datasheet.
- Biology and chemistry — describe the size of a virus (~100 nm) or a molecule (~1 nm) in micrometers and ångströms.
- Semiconductor and thin-film work — turn a 7 nm process node into meters and inches for cross-team reports.
- Imaging and optics — map the wavelength of a filter or LED to its color band and energy.
The output panel shows the value in 9 length units plus THz and eV, so you can switch notation without retyping the number. If you only need to flip between a few specific units, the dedicated tools in our math & conversion category are useful companions. For example, a Micrometer Conversion Calculator is convenient when most of your work lives in the μm range.
How the nm converter works
The calculation uses a single principle: every length unit is a power-of-ten multiple of the meter. To go from one unit to another, multiply by the ratio of their sizes in meters. For light, the converter also applies two extra equations — one for frequency, one for photon energy.
value_in_target = value_in_meters ÷ target_factor_in_meters
The factors are SI-defined. According to BIPM SI Brochure (9th edition), the nanometer is a decimal submultiple of the metre equal to 1×10⁻⁹ m, and the ångström is defined as exactly 1×10⁻¹⁰ m. The micrometer is 1×10⁻⁶ m, the millimeter 1×10⁻³ m, the centimeter 1×10⁻² m, the picometer 1×10⁻¹² m, and the meter 1×10⁰ m. The inch is fixed at exactly 0.0254 m and the foot at 0.3048 m by the international yard & pound agreement.
For light-related outputs, the converter derives frequency in THz and photon energy in eV from the wavelength in nm. The frequency formula uses the speed of light c = 299,792,458 m/s (exact, by SI definition since 1983):
For a 550 nm wavelength, λ(μm) = 0.550, so f ≈ 545.07 THz, which matches the green band of the visible spectrum. The photon energy uses Planck's constant × c, which NIST CODATA lists as 1,239.841984 eV·nm:
A 550 nm photon therefore carries about 2.254 eV. The same formula gives 3.10 eV at 400 nm (violet edge) and 1.77 eV at 700 nm (red edge), bracketing the visible band. Because the factors are exact, the same steps work for any nm input you type. For everyday unit swaps outside the nanometer range, a cm to m Calculator is a faster shortcut.
Key concepts explained
Three ideas make nm conversions straightforward: the SI prefix ladder, the ångström convention, and the photon picture of light. Once you know the ladder, the conversion factors stop looking like something to memorize.
SI prefix ladder
Milli = 10⁻³, micro = 10⁻⁶, nano = 10⁻⁹, pico = 10⁻¹². Each step changes the value by a factor of 1,000.
Ångström
The ångström (Å) equals 10⁻¹⁰ m, so 1 nm = 10 Å. It is common in X-ray diffraction and crystallography.
Visible spectrum
Light visible to humans runs ~400–700 nm: violet 380–450, blue 450–485, green 500–565, red 625–750.
Photon energy
Each photon carries E = hc/λ. With h·c = 1,239.84 eV·nm, green light (550 nm) has E ≈ 2.25 eV.
For astronomical distances, the same prefix idea gives us the light year and parsec, but those are far too large to be reached from nanometers in one step. A Light Year Conversion Calculator handles the jump to interplanetary and interstellar scales once you have a length in conventional metric units.
How to use this nm converter
The workflow is the same whether you start with a wavelength, a particle size, or a semiconductor feature. Type a number, pick the unit it is recorded in, set how many digits you want, and read the result.
Enter your value in the Value field. Try 550 to start with green light or 120 for deep UV.
Pick the source unit from the dropdown. The default is nm, but m, μm, Å, in, and ft are also available.
Choose a decimal precision. Auto switches to scientific notation outside the 10⁻³ to 10⁶ range, which keeps both tiny and large values readable.
Read the source value highlighted at the top, then the full result panel showing 9 length units, plus THz and eV.
Change the source unit dropdown to re-run the conversion from a different starting point — useful when the same record is in inches or ångströms.
Hit Reset to return to 550 nm with auto precision.
The reference panel is most useful when one team uses metric and another uses inches. The full set of length units means you can copy a single number into any system without retyping. For records that are expressed in larger metric units, a Meter Conversion Calculator provides a similar reference panel starting from the meter.
Benefits of using this nm converter
The advantage of a single page that covers 9 length units and 2 light units is that every related value is calculated from the same base number, which removes the rounding error that creeps in when each conversion is done separately. The panel is also a quick cross-check — a wavelength listed as 620 nm in one section and 2.00 eV in another must agree, and the result panel makes that agreement obvious.
• One tool, many units. Convert nm to m, μm, Å, in, ft, THz, and eV on the same screen — no switching between sites.
• Real-time updates. The result panel updates as you type, so iterating on a number takes a single keystroke.
• Bidirectional. Start from any length or light unit and read the same value in every other supported unit.
• Auto scientific notation. Very small (sub-nm) and very large (mm+) values stay readable without manual format switches.
• Significant-figure control. Match the precision of your measurement, lab notebook, or published value with 2/3/4/6/8 sig figs.
• Audit-friendly formula line. The bottom of the panel shows the exact factor used, which helps with reviews and reproducibility.
For most everyday length conversions, the cm to in Calculator is a faster, narrower tool. This page is the right one when the input is at the nanometer scale or when you also want the THz/eV outputs.
Factors that affect results
The arithmetic is exact for the listed factors, but the usefulness of any single number depends on the precision of the original measurement and the meaning of the value being converted. A few factors are worth watching for, because they change how the output should be read.
Source precision
Converted decimals should not imply more certainty than the source measurement supports. A 1 nm input cannot give 1×10⁻⁹ m more accurate than ±0.5 nm.
Unit choice
Pick the unit that matches the original record. Re-converting 1 μm as 1,000 nm and then to meters introduces an extra rounding step.
Length vs. light
THz and eV outputs only make sense if the input is a wavelength of light. Using nm for a particle size still gives a number, but the THz/eV will not be physically meaningful.
Medium of propagation
The THz output assumes vacuum. For light in a medium with refractive index n, divide the displayed frequency by n to get the in-medium value.
As published by NIST CODATA, the speed of light in vacuum is exactly 299,792,458 m/s by definition of the metre. That value, combined with the 1,239.84 eV·nm constant, is what lets the calculator produce the THz and eV outputs without empirical correction. For broader energy work, an Energy Converter translates between electronvolts, joules, and other common energy units.
Frequently Asked Questions
How many nanometers are in a meter?
There are exactly one billion nanometers in a meter (1 m = 1,000,000,000 nm = 1×10⁹ nm). The reverse is just as clean: 1 nm = 1×10⁻⁹ m. This fixed relationship is what makes an nm converter precise to whatever number of significant figures you need.
How do I convert nm to m?
To convert nm to m, divide the value in nanometers by 1,000,000,000 (or 1×10⁹). For example, 450 nm ÷ 1×10⁹ = 4.5×10⁻⁷ m. Our nm converter does this for you instantly and shows the result in scientific notation.
How do I convert nm to angstrom?
Multiply the value in nanometers by 10, since 1 nm = 10 Å (the ångström is exactly 1×10⁻¹⁰ m). So 25 nm = 250 Å. Use the calculator above to convert nm to Å, Å to nm, or any other length unit in one step.
What is the formula to convert wavelength (nm) to frequency (THz)?
Use f(THz) = 299.792458 / λ(μm). For example, 550 nm = 0.550 μm, so f = 299.792458 / 0.550 ≈ 545.07 THz, which is green light. Our nm converter also returns THz directly from any wavelength you type in nm.
How do I convert wavelength in nm to photon energy in eV?
Apply the photon-energy equation E(eV) = 1,239.84 / λ(nm), where the constant is Planck's constant times the speed of light in eV·nm. For instance, a 620 nm red photon has E = 1,239.84 / 620 ≈ 2.00 eV. Type your wavelength into the calculator to get this in eV automatically.
What wavelength range is visible light in nanometers?
Visible light spans roughly 400–700 nm, with violet near 380–450, blue 450–485, green 500–565, yellow 565–590, orange 590–625, and red 625–750 nm. Below 400 nm is ultraviolet; above 700 nm is infrared.