RC time constant calculator

RC Time Constant Calculator

Compute τ = R·C and fc = 1/(2πRC), or solve for R/C from a target τ or fc. Compare to nearest standard values (E-series).

Mode

Resistor R

Capacitor C

Target τ

Target fc

Invalid input. For τ/fc modes provide R and C. For Solve R provide C and (τ or fc). For Solve C provide R and (τ or fc).

Precision:

τ (ideal)

fc (ideal)

Solved R (ideal)

Solved C (ideal)

Nearest resistor series

Nearest capacitor series

R (nearest standard)

C (nearest standard)

τ (rounded)

fc (rounded)

Error vs target/ideal

τ = R·C, fc = 1 / (2πRC)