basic

RC Circuit Time Constant Calculator

τ = RC — time for capacitor to charge to 63.2%.

Calculates the RC time constant and the capacitor voltage/charge at any elapsed time during charging or discharging.

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
Was this helpful?

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 × (1 − e^(−t/τ))

In depth

Calculates the RC time constant and the capacitor voltage/charge at any elapsed time during charging or discharging.