Pension Drawdown Calculator, Years of Income & Sustainable Withdrawal

A real return, after inflation, so the answer stays in today's purchasing power. Balanced portfolios have historically returned roughly 3–5% real over long periods; cash and bonds sit lower. The calculator deliberately keeps inflation out of the math so you only deal with one number.

The 4% rule says a first-year withdrawal of 4% of the portfolio, inflation-adjusted, historically survived 30-year retirements. $750,000 × 4% = $30,000/year = $2,500/month, well below the $3,580 the strict 30-year amortization at 4% allows, because the 4% rule builds in bad-sequence protection this formula does not.

Sequence-of-returns risk is the big weakness of any smooth-rate model: losses in the first years of withdrawals do far more damage than the same losses later. Treat the answer as a planning median, keep a cash buffer, and stress-test with a zero-return run (enter 0% to see the no-growth floor).

Yes, conceptually: subtract guaranteed pension income from your monthly spending first, then draw down only the remainder from the pot, that shrinks W and stretches the pot considerably.

No. It is the exact amortization of the pot at the assumed rate, if the real return comes in lower, or you live past 30 years, the money can run short. It is a floor for comparison, not a promise.