# Q Factor Calculator

Calculate the Quality Factor of a coil or capacitor with the Q Factor Calculator and learn on the go with the integrated live example

The quality factor of a resonator is related to the bandwidth and is a measure of its resonant frequency response. High Q resonators have a narrow bandwidth so will only respond to and work on a narrow band of frequencies. This makes them more difficult to tune, but they perform better at resonance than low Q resonators. For example, a coil with a high Q value will have greater resonant voltage rise than a low Q coil.

The formula for calculating the Q factor of an inductor or capacitor is:

Where*Q* = Quality Factor*X* = Reactance in ohms*R* = Resistance in ohms

**Example 1:** Find the Q factor of an inductor that has a inductive reactance of 2400 Ohms and series resistance of 3.5 Ohms

**Example 2:** Find the Q factor of a capacitor that has a capacitive reactance of 4000 Ohms and series resistance of 5 Ohms

Use the calculator below to see a live example.

### Using the Q Factor Calculator

**Reactance:** Enter the inductive or capacitive reactance

**Resistance:** Enter the series resistance

**Units:** You can choose your preferred units of measurement through selecting the units cells and clicking the arrow to display a list of available options

**Learn As You Go:** This feature displays a live example of how to calculate Q Factor using the figures that you enter

*Reference: ARRL – The Radio Amateur’s Handbook*

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