State Pension deferral calculator — is waiting worth it?

Deferring adds a permanent 1% for every 9 weeks (about 5.8% a year) to every later payment — in exchange for the income you give up while waiting. This calculator finds your honest breakeven age using the same statutory rules the Hundred Summers engine models. Your figures never leave your browser.

How deferral works

You do not have to take your State Pension at State Pension age — it starts only when you claim it. Under the new State Pension (reaching State Pension age after April 2016), every 9 weeks you wait adds 1% to every later payment: about 5.8% for each full year, permanent, applied on top of whatever annual increases happen. There is no lump-sum option under the new rules (that was the old system).

The honest arithmetic

Deferring one year gives up a full year of pension — roughly £12,500 at the full rate — to gain about £730 a year for life. Divide one by the other and the breakeven sits roughly 17 years out: around age 83–84. UK life expectancy at 66 is about 85 for men and 87 for women, with half living longer — so deferral is close to a fair bet on average, better if your health and family history point long, worse if they do not.

The stronger case is often tax: if you work past State Pension age, the pension stacks on top of your earnings and is taxed at your marginal rate — 40% for higher-rate earners. Defer until you stop, and the same income lands in years where it may be covered by your personal allowance or basic rate. The full Hundred Summers plan models deferral inside your whole retirement picture, tax included, alongside everything else.