Life expectancy calculator — honest about being an estimate

ONS cohort baselines, evidence-weighted lifestyle adjustments (deliberately clamped — stacked risk factors overlap in real mortality data), and the number that matters for money: the plan-to age with the buffer planners add. The same model that sets the Hundred Summers app's horizon. Your figures never leave your browser.

A mid-point, not a deadline

Every life-expectancy figure is the middle of a wide distribution: about half of people outlive theirs, many by a decade. That's why the planning question is not "when will I die?" but "what horizon takes the worst case off the table?" — and why the answer this page leads with is the buffered plan-to age, not the estimate itself. The cost of being wrong is asymmetric: plan long and you leave an inheritance; plan short and the money runs out at the age you are oldest and least able to work.

The adjustments are evidence-weighted and deliberately bounded — smoking, inactivity, diabetes and heart disease overlap heavily in real mortality data, so stacking them without a clamp manufactures false precision (this model also gives no longevity credit for alcohol; the protective J-curve is now considered an artefact). The full Hundred Summers plan uses this exact model to set your horizon, then tests whether the money survives it — including a longevity-stretched decade beyond.