Frequency to Wavelength Converter

How to use this calculator

1. Decide what electromagnetic frequency you want to analyze (for example, a Wi‑Fi band, a radio channel, or an optical frequency in the visible/IR/UV range).
2. Convert that frequency to hertz if it’s currently in MHz, GHz, or THz (for example, 2.4 GHz = 2.4 × 10⁹ Hz).
3. Enter the frequency in Hz into the calculator.
4. We divide the speed of light in vacuum by your frequency to compute wavelength in meters, then multiply by 10⁹ to show nanometers.
5. Use the meter value for RF/antenna work and the nanometer value for optics and photonics context.

Inputs explained

Frequency (Hz)

The electromagnetic wave frequency in hertz. Use scientific notation for very large values (for example, 5e14 for 500 THz). If your frequency is in MHz, GHz, or THz, convert to Hz before entering.

When to use it

• Choosing antenna lengths or feed‑line dimensions for RF projects by starting from frequency and getting quarter‑ or half‑wave dimensions.
• Mapping optical frequencies or photon energies to wavelengths when selecting filters, lenses, or detectors in spectroscopy or imaging setups.
• Relating different parts of the EM spectrum—radio, microwave, infrared, visible, ultraviolet, X‑ray—using wavelength instead of frequency for educational or lab work.
• Cross‑checking textbook or datasheet values where some sources quote frequencies and others quote wavelengths, ensuring they are consistent.

Tips & cautions

• Always convert your input frequency to hertz before entering it. For example, 100 MHz = 1e8 Hz, 2.4 GHz = 2.4e9 Hz, 560 THz ≈ 5.6e14 Hz.
• Remember that wavelength shortens inside materials with refractive index n; the vacuum wavelength λ₀ relates to material wavelength by λ_material = λ₀ ÷ n.
• For rough antenna design, a quarter‑wave dimension is λ ÷ 4 and a half‑wave is λ ÷ 2; use the meter output for those calculations.
• Use scientific notation to avoid typing many zeros—this reduces input mistakes when working with very high‑frequency signals.
• Assumes propagation in vacuum with speed c; it does not automatically adjust for refractive indices or waveguides where phase velocity differs from c.
• Models a single frequency at a time; it does not address bandwidth, modulation sidebands, or spectral width.
• Displays rounded values for readability; if you need very high precision for lab work, you may need to carry more significant figures manually.

Worked examples

Deep dive

FAQs

Can I adjust for propagation in glass, water, or other media?

Yes, indirectly. Divide the speed of light c by the medium’s refractive index n to get an effective velocity (c_eff = c ÷ n), then use λ = c_eff ÷ f. This calculator uses vacuum c by default, so you would need to adjust f or c offline for precise in‑medium values.

What units should I use for frequency?

Enter frequency in hertz. If you have MHz, GHz, or THz, convert first (for example, 2.4 GHz = 2.4e9 Hz, 1 THz = 1e12 Hz). Using consistent SI units avoids scaling mistakes.

Does this work for all parts of the EM spectrum?

Yes, as long as you enter a frequency in hertz. The same λ = c / f relationship applies from radio waves through microwaves, infrared, visible light, ultraviolet, and X‑rays in vacuum.

Why doesn’t the calculator ask for medium or temperature?

To keep it simple, we assume vacuum speed of light. In many contexts, especially for quick design checks or homework problems, this is the assumption being used. For detailed modeling in specific media, you’d typically use more specialized tools.

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