£100,000 pension pot: enough to bridge to the State Pension, not to replace it

Retiring at 60 on £100,000 means drawing 13.8% of the pot in the first year — two and a half times the 4% rule of thumb, and a rate no sustainable-withdrawal study would endorse for a pot expected to last decades. Our projection still reports it as sustainable, and the reason is not optimism: the pot is not being asked to last decades. It is being asked to last until the State Pension arrives, after which it is largely spent.

That is the crucial difference between this pot size and a larger one, and it is why 4%-rule reasoning misleads here. The rule prices a portfolio that must fund a whole retirement. £100,000 is funding a fixed, short, known gap — a different problem, with a legitimately much higher safe rate.

Because £100,000 does not survive the bridge from 50 to 67, the years after that are funded by the State Pension close to alone — about £11,502 a year in today's money, assuming a full contribution record. Our projection carries that through to 95, which is why the income figure for the earliest ages looks flat rather than tapering: there is nothing left to taper.

This is the part most calculators obscure by quoting a single lifetime average. Two very different decades are being averaged together — a funded bridge and an unfunded remainder — and the average flatters both. Retiring at 60 instead of 50 does not merely raise the income; it changes whether there is a pot left at all once the State Pension starts.

The ISA slice of £100,000 — £30,000 at the start, drawn alongside the pension — is exhausted at about age 64 retiring at 50. Up to that point part of your income arrives with no tax at all, which is what keeps the early effective rate low. After it, withdrawals come from the SIPP alone and every pound above the personal allowance is taxable.

That transition is worth planning around rather than discovering. It is the reason two plans with the same headline income can feel different a decade in, and the reason ISA and pension are worth drawing in a deliberate order rather than proportionally.

Across the ages on this page, £100,000 pays between £94,000 and £184,000 in income tax over the whole plan, and some years cross into the higher-rate band. That is not a rounding error against the pot itself, and unlike growth it is substantially within your control.

Three levers move it. A quarter of each pension withdrawal is tax-free, so the order you draw wrappers in changes the bill; the years before the State Pension starts have an unused personal allowance in them that is gone if you do not use it; and once the State Pension arrives it absorbs most of that allowance permanently, so income deferred into those years is taxed harder than income taken before them. Our calculator prices all three against your actual numbers.

On the optimised plan the SIPP inside £100,000 is emptied by age 51 — 1 year of retiring at 50 — and the ISA grows to £65,410 over the same period. The pot is not running out: the money is moving wrapper to wrapper, and the reason is tax.

In the years before the State Pension starts you have a personal allowance and a basic-rate band doing nothing. Drawing the pension down then — faster than you need to spend it, and re-sheltering the surplus in an ISA — uses that allowance while it is free. Leave the money in the SIPP instead and it is still taxable later, except that by then the State Pension has absorbed the allowance and every pound is taxed from the first. At £100,000 the whole SIPP fits inside those first couple of years' allowances, so the conversion is quick and close to costless.

This is the single biggest lever the calculator finds that a spreadsheet usually misses, and it is worth £90,000 or so across the age range on a pot this size.

Retiring at 60, £100,000 supports £13,800 a year against the £13,900 the Retirement Living Standards attach to a minimum single-person retirement. The shortfall is £133 a year — real, but small enough to be a planning problem rather than a savings problem.

That distinction changes what to do next. A gap this size does not need a bigger pot; it needs the withdrawal order tuned — drawing wrappers in a different order, using the bridge years' spare personal allowance, or accepting one more year of work. Any one of those closes £133 on its own, which is why a pot-size-only comparison against the benchmark is the wrong way to read this page.

Going from £100,000 to £150,000 adds about £3,200 a year retiring at 50, and £2,200 a year retiring at 60. Put the other way, that extra £50,000 pays itself back as income over roughly 23 years of retirement.

Compare that with what the same effort buys through the retirement age instead: one more year of work is worth about £700 a year on this pot. On those numbers the extra saving is the stronger lever, which is unusual and specific to this pot size. See £150,000 in full →

Every year you delay is a year you are not funding from the pot and a year of bridge you no longer have to cross, which is why the gain compounds rather than accumulating. On £100,000 the difference between stopping at 50 and stopping at 60 is about £6,900 a year — roughly £700 for each year waited, on identical savings.

At this pot size that arithmetic dominates everything else on the page. No plausible change in investment growth moves the outcome as much as the retirement age does, because the binding constraint is the length of the unfunded gap, not the return on the money.