Frequency Bandwidth Calculator
Compute bandwidth (BW) from two band-edge frequencies, center frequency, fractional bandwidth, Q factor, and bandwidth in octaves — plus a two-way solver. All calculations run in your browser.
Bandwidth from fL and fH
Solver: find one frequency from the others
Octave, Q, and fractional BW conversion
Verified examples
20 MHz, fc = 2422 MHz, fractional BW = 0.8258%,
Q = 121.1, width = 0.01191 octaves.
20 MHz, fc = 98 MHz, fractional BW = 20.4082%,
Q = 4.9, width = 0.29546 octaves.
10 kHz (fL = 995 kHz, fH = 1005 kHz).
Frequently asked questions
What is frequency bandwidth?
Frequency bandwidth is the difference between the upper band-edge frequency (f_H) and the lower band-edge frequency (f_L): BW = f_H − f_L. It expresses the width of the frequency band occupied by a signal or passed by a filter.
How do you compute the Q factor?
Q factor = f_c / BW, where f_c = (f_H + f_L) / 2 is the center frequency. Example WiFi 20 MHz channel: f_c = 2422 MHz so Q = 2422 / 20 = 121.1. High Q means a narrow, selective band.
What is fractional bandwidth?
Fractional bandwidth = BW / f_c, the bandwidth relative to the center frequency, usually in percent. Example FM band 88–108 MHz: BW = 20 MHz, f_c = 98 MHz, so fractional BW = 20 / 98 = 20.4082%.
How are Q factor and fractional bandwidth related?
They are reciprocals: Q = 1 / fractional BW. Fractional BW 20.4082% (0.204082) means Q = 1 / 0.204082 = 4.9.
What is bandwidth in octaves?
Bandwidth in octaves = log2(f_H / f_L). One octave means f_H = 2 × f_L. Example WiFi 20 MHz channel (2412–2432 MHz) is only 0.01191 octaves wide.
How do you find f_H given BW and f_L?
Use f_H = f_L + BW. Example: f_L = 2412 MHz and BW = 20 MHz give f_H = 2432 MHz.
How does this tool differ from Frequency Converter?
This tool computes bandwidth, Q factor, fractional bandwidth, and octaves from two band-edge frequencies. Frequency Converter handles frequency unit conversion, period, wavelength, angular frequency, and Nyquist rate.
What is the bandwidth of a WiFi 20 MHz channel?
A WiFi 20 MHz channel (e.g. 2412–2432 MHz) has BW = 20 MHz, center frequency f_c = 2422 MHz, fractional BW = 0.8258%, Q = 121.1, and 0.01191 octaves wide.
Free tool by NRTechStudio