Capacitor Charge Time Calculator
τ = RC and the exponential approach toward supply voltage.
Capacitance unit
τ = RC
1000 ms
~63.2% (1τ)
999.7 ms
~95% (~3τ)
2.996 s
~99% (~5τ)
4.605 s
Charge curve V(t) = Vs(1 − e−t/τ), 0 → 5τ
What is this tool?
In a series RC circuit, voltage on the capacitor approaches Vs as V(t) = Vs (1 − e^(−t/τ)) with τ = R·C. About 63.2% of the final value occurs at t = τ; ~95% near 3τ and ~99% near 5τ.
How to use it
- Enter R and C (with unit toggle) and supply voltage if you want absolute volts on the chart.
- Read τ and times to common charge percentages.
- Remember ESR, leakage, and non-ideal parts change real timing.
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