Wavelength ↔ Frequency Calculator
Convert both ways with velocity factor for coax and PCB — plus λ/2, λ/4 and the λ/10 EMC rule of thumb computed live.
The λ/10 figure is the EMC rule of thumb: structures shorter than λ/10 behave as lumped elements; longer ones act as transmission lines/antennas — that's when ringing, stubs and termination start to matter. In coax, electrical length = physical/VF, which is why a “quarter-wave” matching stub of RG-58 is only ~66 % of the free-space length.
Wavelength Frequency Calculator computes wavelength ↔ frequency conversion with velocity factor for cables and PCB — free, instant and private in your browser. RF designers, EMC engineers using the λ/10 rule and antenna builders use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About Wavelength ↔ Frequency Calculator
Wavelength Frequency Calculator computes wavelength ↔ frequency conversion with velocity factor for cables and PCB using the standard engineering relation: λ = c·VF/f — VF = 1 in air, ~0.66 solid-PE coax, ~0.82 foam coax, ~0.5 in FR-4. Worked live: 433.92 MHz is 69.1 cm in air — so a quarter-wave wire antenna for it is ~16.4 cm. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use Wavelength ↔ Frequency Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use Wavelength ↔ Frequency Calculator?
- ✓Implements the real formula — λ = c·VF/f — VF = 1 in air, ~0.66 solid-PE coax, ~0.82 foam coax, ~0.5 in FR-4 — with the substitution shown, not a black box
- ✓Built for RF designers, EMC engineers using the λ/10 rule and antenna builders
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate wavelength frequency?+
Wavelength ↔ frequency conversion with velocity factor for cables and PCB follows λ = c·VF/f — VF = 1 in air, ~0.66 solid-PE coax, ~0.82 foam coax, ~0.5 in FR-4. For example, 433.92 MHz is 69.1 cm in air — so a quarter-wave wire antenna for it is ~16.4 cm. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
What is velocity factor and when do I need it?+
EM waves slow down in dielectrics by 1/√εr. A 'quarter-wave' coax stub must be physically only ~66 % of the air length; PCB traces are 'electrically longer' than they look. Any time a length is specified in wavelengths inside a material, multiply by VF.
Why does λ/10 matter in EMC and layout?+
Structures shorter than ~λ/10 behave as lumped circuit elements; longer ones become transmission lines and accidental antennas — reflections, ringing and radiation start there. At 100 MHz that threshold is just 30 cm in air, ~15 cm in FR-4.
Is the Wavelength Frequency Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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