How Long Will My Savings Last

Estimate your drawdown “runway” given withdrawals, expected returns, inflation, fees, and other income. Toggle inflation-adjusted withdrawals to keep spending power constant. This tool shows a deterministic projection (one path); see the notes below for caveats and sequence-of-returns risk.

Inflation-adjustedFeesOther incomeChart

Inputs

Returns, inflation, and fees are combined to a monthly real return via the Fisher relationship. “Inflation-adjust” keeps amounts in today’s purchasing power by growing them with monthly inflation.

Results

Status
Depletes

Estimated runway: 11 years 7 months

Ending Balance at Horizon
$0.00

May be 0 if depleted before horizon.

Real returnsCOLA toggleFees

Methodology (what’s under the hood)

We project month by month. Nominal return and inflation are converted to a real return via the Fisher relationship, then to monthly. We debit the withdrawal (optionally inflation-adjusted), add other income, and grow the remaining balance by the monthly real return after fees. If withdrawals are sustainable in real terms (i.e., a perpetuity condition holds), we report “Sustainable (no depletion)”.

References: time-value/annuity math (present value of annuity & perpetuity), Fisher equation (real vs nominal), and sequence-of-returns risk (deterministic projections don’t show path risk).

Notes & best practices

  • Inflation adjustment: Turning this on keeps spending power steady; the model increases withdrawals by monthly inflation.
  • Fees: Annual fee reduces return; we apply it evenly across months.
  • Other income: E.g., pension or rental income. Turn on inflation-adjust to preserve real purchasing power.
  • Runway vs. “4% rule”: The classic safe-withdrawal research gives long-horizon guidance but doesn’t guarantee outcomes. Use this tool to sanity-check your personal numbers and risk tolerance.

Educational only; not financial advice. For complex cases, consult a fiduciary advisor.