How does the State Pension change my Coast FIRE number?

From your State Pension age onwards, the pension covers part of your spending, so your portfolio only needs to fund the difference plus the bridge years before it starts. For most people that cuts the target by 20-40% compared with ignoring it.

What State Pension amount does the calculator use?

It defaults to the full new State Pension for 2026/27, £241.30 a week or about £12,548 a year, and you can change it to match your own forecast from the government's Check your State Pension service.

Are the results in today's money?

Yes. The calculator works in real terms: your inflation assumption is subtracted from your investment return, so every figure is in today's pounds.

UK Coast FIRE Calculator (2026) — Your Number in Pounds, With State Pension

Why a UK-specific Coast FIRE calculator?

Most Coast FIRE tools quietly assume an American retirement: no state provision, one big pot, healthcare cliff at 65. The UK picture is different in two ways that change your number a lot:

The State Pension is real money. The full new State Pension is £241.30 a week (about £12,548 a year) from April 2026. If you spend £30,000 a year, the pension covers more than a third of it from your State Pension age onwards, your portfolio only has to fund the rest, plus the bridge years before it starts. Ignoring it means dramatically over-saving.
Your money unlocks in stages. ISAs are accessible any time; personal and workplace pensions unlock at 55, rising to 57 from April 2028; the State Pension arrives at 66-68 depending on your birth year. A UK coast plan is really a bridge plan, see the full UK Coast FIRE guide.

How the maths works

Target at stop-work age = bridge years of full spending (discounted) + post-pension pot for (spending − State Pension) ÷ withdrawal rate
Coast number today = that target ÷ (1 + real return)^{years until you stop work}

Everything is in today's pounds. The calculator prices the years between stopping work and your State Pension age at your full spending, then prices the years after at your spending minus the pension, and discounts the whole thing back to today at your real (after-inflation) return. Toggle the State Pension off to see how much heavy lifting it does.

Check your own forecast at gov.uk's "Check your State Pension" service, the full amount needs 35 qualifying years of National Insurance, and the calculator lets you enter your actual forecast instead of the default.

Frequently asked questions

Which pots should I count as "currently invested"?

Everything earmarked for retirement: workplace and personal pensions (SIPPs), Stocks & Shares ISAs, and any general investment account you intend to spend in retirement. Leave out your emergency fund and home equity.

What if I'll retire before my pension unlocks at 57?

Then your ISA and taxable accounts have to carry you to 57, the "ISA bridge." The maths above still holds for the total, but check the split: a big pension and empty ISA can leave you asset-rich and bridge-poor. The UK guide walks through it.

Should I use 4% in the UK?

The 4% rule comes from US market history. Many UK planners prefer 3.5% for long retirements, drop the withdrawal-rate slider and watch the number move. The 4% rule calculator shows the sensitivity.

Does the calculator store my data?

No. It runs entirely in your browser; nothing you type leaves your device.

More FIRE calculators

Coast FIRE UK GuideThe full maths in pounds, ISAs and SIPPs. Coast FIRE CalculatorThe classic version, five currencies. Savings Rate CalculatorYears to FI from your savings rate. Early Retirement CalculatorThe age you can actually retire.

Sources and further reading

Rules and figures on this page are drawn from the primary sources below, so you can verify them directly rather than take our word for it.

Calculators for other countries

India FIRE CalculatorBuilt on India's own retirement system.Australia FIRE CalculatorBuilt on Australia's own retirement system.Canada FIRE CalculatorBuilt on Canada's own retirement system.Ireland FIRE CalculatorBuilt on Ireland's own retirement system.Singapore FIRE CalculatorBuilt on Singapore's own retirement system.New Zealand FIRE CalculatorBuilt on New Zealand's own retirement system.