The ISA bridge — can you get from here to your pension?

Retire before your pension unlocks and there is a gap only accessible money can cross: ISAs, taxable savings, cash. This calculator tests your bridge with the Hundred Summers app's real projection — pensions locked until the statutory access age, ISA drawn tax-free, income tax charged properly once the pension opens — and finds the smallest accessible pot that funds every year. Your figures never leave your browser.

The constraint that shapes FIRE in the UK

Pension contributions get the best tax treatment in UK saving — and a lock that makes them useless for the years that define early retirement. The bridge inverts normal planning logic: for the bridge years, what matters isn't tax efficiency but accessibility, so early retirees deliberately fund ISAs past the point a pure tax optimiser would. The balance point depends on your retirement age: each year earlier adds a year of spending to the bridge AND removes a year of contributions and growth.

Run the numbers both ways: this page finds the accessible pot your date needs, and the when-can-I-retire calculator finds the earliest date your pots allow. The engine locks pensions at today's statutory 55 — rising to 57 in April 2028, so treat a post-2028 plan as needing two more bridge years (the conservative reading). A market crash early in a bridge is sequence risk at its sharpest; the full Hundred Summers plan stress-tests your bridge through thousands of simulated markets and every historical sequence since 1928, with your real accounts and spending phases.