LC resonant frequency calculator
Choose what to solve and the loss-resistor topology. Enter your own values; no component, resistance or tolerance values are prefilled.
LC resonant frequency calculator
Choose what to solve and the loss-resistor topology. Enter your own values; no component, resistance or tolerance values are prefilled.
L[mH]×10⁻³→H; C[µF]×10⁻⁶→F. f₀=1/(2π√(LC)); X=√(L/C); C=1/[L(2πf)²]; L=1/[C(2πf)²]. Series Q=X/R; parallel Q=R/X; BW=f₀/Q. Single-component error e: f′=f₀/√(1+e/100); shift=(f′/f₀−1)×100%.
Ideal LC frequency with an explicitly selected loss-resistor Q model. R blank or zero omits Q and bandwidth rather than returning zero. No damped-frequency, parasitic, winding-loss, current-rating or practical design model is inferred.
Endpoints use the source’s centred approximation f₀ ± BW/2. They are not exact half-power frequencies or a measured passband, especially at low Q.
Calculated in your browser. Inputs are not uploaded or stored.
- Inductance (mH)
- Capacitance (µF)
- Ideal frequency / forward check (Hz)
- Reactance at resonance (Ω)
Unavailable: R is blank or zero; Q, bandwidth and endpoints are omitted.
- Quality factor Q
- Bandwidth f₀/Q (Hz)
- Approximate lower endpoint (Hz)
- Approximate upper endpoint (Hz)
The approximate lower endpoint is negative. A negative frequency has no physical passband meaning; this approximation is not clamped.
Substitution and forward calculation
| Component error (%) | Frequency shift (%) | Resulting frequency (Hz) |
|---|
A QUICK WALKTHROUGH
How to use this tool
- Choose the solve mode and resistor topology.
- Enter the required component or target values, optional R and your component-error list.
- Calculate and review the substitution, forward check and tolerance table; copy or download the report.
Substitution and forward calculation
L[mH]×10⁻³→H; C[µF]×10⁻⁶→F. f₀=1/(2π√(LC)); X=√(L/C); C=1/[L(2πf)²]; L=1/[C(2πf)²]. Series Q=X/R; parallel Q=R/X; BW=f₀/Q. Single-component error e: f′=f₀/√(1+e/100); shift=(f′/f₀−1)×100%.
Loss-resistor topology
Ideal LC frequency with an explicitly selected loss-resistor Q model. R blank or zero omits Q and bandwidth rather than returning zero. No damped-frequency, parasitic, winding-loss, current-rating or practical design model is inferred.
Single-component errors (%)
Enter 1–20 errors separated by commas or whitespace. Use a dot for decimals. Each error must be greater than −100%. Only one component changes; the other stays fixed.
Calculated in your browser. Inputs are not uploaded or stored.
Calculated in your browser. Inputs are not uploaded or stored.
GOOD TO KNOW
Common questions
What do the bandwidth endpoints mean?
Endpoints use the source’s centred approximation f₀ ± BW/2. They are not exact half-power frequencies or a measured passband, especially at low Q.