basic

RC Circuit Time Constant and Voltage Decay Calculator

τ = RC; V(t) = V₀·e^(−t/τ) — capacitor discharge.

Calculates RC time constant τ = R·C, voltage at time t: V(t) = V₀·e^(−t/τ), charge remaining Q(t), and the time to reach 50%, 37%, and 10% of initial voltage.

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

Ω
F
V
s

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

τ = R·C; V(t) = V₀·e^(−t/τ)

In depth

Calculates RC time constant τ = R·C, voltage at time t: V(t) = V₀·e^(−t/τ), charge remaining Q(t), and the time to reach 50%, 37%, and 10% of initial voltage.