RC Settling Time Calculator
Estimate transient settling for a single ideal first-order RC response. Pick the fraction of the final change you want completed; the remaining error decays exponentially.
Method, example, and limits
Formula: τ = RC; fraction settled = 1 − e^(−t/τ), so t = −τ ln(1 − fraction settled).
Inputs and units: R is resistance in ohms, C is capacitance in microfarads (converted internally to farads), and settled percentage is between 0.01% and 99.99%.
Worked example: For R = 10 kΩ, C = 10 µF, τ = 0.1 s. Reaching 99% settled takes −0.1 ln(0.01) ≈ 0.460517 s.
Assumptions: A single linear, first-order RC network responds to an ideal step with zero-state exponential behavior. The input percentage is fraction of the total change completed, not percent error remaining.
Limits: Multi-pole circuits, loading, parasitics, nonlinear components, and initial conditions can change settling. This calculation does not select components or provide electrical installation recommendations.
Creator & reviewers
Creator persona
- Casey RowanUnits, conversions & measurement
Reviewer personas
- Devon ShawFormula & assumptions review
- Sage MitchellClarity & usability review