Frequency, Wavelength & Period
Connect repetition rate to period, propagation distance, delay, and electrical length.
- Typical inputs
- Frequency or period, unit scale, velocity factor, and an optional physical length.
- Calculated output
- Period, guided wavelength, quarter/half wave, propagation delay, wavelengths, and electrical degrees.
- Model status
- Release A · documented and numerically tested
How large is one cycle in time and in this propagation medium?
Time and distance scale
Frequency is unchanged by the medium model; velocity factor changes phase velocity and wavelength. Enter an optional physical length to expose delay and phase.
- Period
- 408.163 ps
- Quarter wave
- 30.5911 mm
- Half wave
- 61.1821 mm
- Phase velocity
- 299.792 Mm/s
- Delay over length
- 100.069 ps
- Length in wavelengths
- 0.245170 λ
- Electrical length
- 88.2611°
Calculation path
- Higher frequency does not itself make propagation faster in the same medium.
What this calculator is doing
Frequency fixes the time per cycle. Exact c multiplied by velocity factor gives phase velocity; dividing by frequency gives wavelength. A physical length is then expressed as delay and phase.
How to read the result
Compare physical length with wavelength before assuming a lumped model. A cable or PCB trace can be electrically long even when it looks mechanically short.
Equations & conventions
- f is frequency in hertz and T is period in seconds.
- VF is phase velocity divided by exact c.
- ℓ is physical length; θ is phase length in degrees.
Independently checked example
Checked example: 2.45 GHz in free space has a 408.1633 ps period and 122.3643 mm wavelength; 30 mm is 88.2610°.
Common mistakes
- Assuming higher frequency travels faster in the same medium.
- Using free-space wavelength inside a dielectric.
- Treating a fixed physical length as the same phase shift at every frequency.
- Confusing one-way delay with round-trip delay.
Assumptions, validity & omissions
- Velocity factor is constant over the entered frequency.
- Free-space speed uses exact c.
- Electrical length is phase delay, not physical size alone.
Sources & model provenance
- NIST SP 330 (2019), The International System of Units (opens in a new tab) — Exact SI defining constants c and k. Accessed 2026-09-05.