Frequency ↔ Wavelength

Convert frequency to wavelength (and back) using λ = v / f and f = v / λ. Choose a speed preset (speed of light, typical coax, etc.) or enter a custom velocity.

How to Use

  1. Enter either Frequency or Wavelength (or both).
  2. Select the correct units (GHz, MHz, nm, m, etc.).
  3. Pick a speed preset or set a custom propagation velocity.
  4. Open Show Work for base-unit steps and formulas.
Signal Readout
Live values with unit scaling. Work shown in base units (Hz, m, m/s).
f
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λ
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v
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Status: —
Inputs & Settings
Enter frequency or wavelength. Choose propagation speed (v). Results update instantly.
Examples: 100 MHz (FM), 2.4 GHz (Wi-Fi), 1575.42 MHz (GPS L1)
Examples: 0.125 m (12.5 cm), 1 m, 550 nm (green light)
Velocity factor (VF) is common for coax/lines. Use Custom for exact cable specs.
Show Work (step-by-step)
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Work is shown in base units (Hz, m, m/s). Output units may be auto-scaled for readability.

Formulas

Core relationship: v = f × λ

  • Wavelength: λ = v ÷ f
  • Frequency: f = v ÷ λ
  • Period: T = 1 ÷ f
Where v is propagation speed (m/s), f is frequency (Hz), λ is wavelength (m), and T is period (s).

FAQ

Why does wavelength change with cable type?

In a transmission line (like coax), signals travel slower than in free space. That lowers v, which lowers λ for the same frequency. This is often expressed as velocity factor (VF), where v = VF × c.

Is the “speed of light” always correct?

It’s correct for vacuum and very close for air. For cables, PCB traces, and many materials, use VF or a custom velocity.

What is period and why include it?

Period (T) is the time for one cycle. It’s helpful for timing/clock work: T = 1/f.

Can I use this for light (nm range)?

Yes—set velocity to speed of light (or air approx). For precise optics in materials (glass/water), use a custom velocity derived from refractive index.

Tool Info

Last updated:

Updates may include additional unit support, preset tuning, and edge-case handling.