What is the Coast FIRE Calculator?
The Coast FIRE Calculator helps you work out how much you need invested today so that, with no further pension or ISA contributions, your money can grow to fund retirement later. It’s designed for UK investors who want to know when they can stop aggressively saving for retirement and simply “coast” on a lower-stress income that just covers day-to-day living costs.
How the Calculator Works?
This calculator models your retirement goal amount, target retirement age and expected investment growth to find the pot size you need today for Coast FIRE. It projects how that pot could grow over time with compound returns and no further contributions, then compares it with your chosen retirement income needs, withdrawal rate and any State Pension you choose to include. You can also add your current pensions, ISAs and GIAs to see how close you already are to your Coast FIRE number.
Step One: Set Your Retirement Target
Choose your target retirement age and the annual income you’d like in retirement. Add your expected safe withdrawal rate and decide whether to include the State Pension in your plan.
Step Two: Enter Your Current Investments
Add your existing pension, ISA and GIA balances, plus any other long-term investments. Set your assumed long-term growth rate so the calculator can project how your pot might grow between now and retirement.
Step Three: Discover Your Number
The calculator shows the pot size you’d need today to reach your retirement goal without any further contributions. It then compares this to your current investments so you can see how close you are to Coast FIRE and how tweaks to growth, retirement age or income affect your path.
Disclaimer:
This calculator provides illustrative projections only and should not be taken as financial advice. Investment returns and personal circumstances can change over time, so consider speaking with a qualified financial adviser before making major financial decisions.
What does retirement mean to you?
Traditional retirement is broken. Understand how our calculator enables you to live a better life now vs later.
Retire from corporate work?
Use the tool to utilise how you can step away from the corporate world and live life on your own terms.
Work less, live more
See how part-time or project-based work can bridge your income gap while giving you more time for life.
Freedom through planning
Understand how your savings, spending and investments can work together to buy back your time.
Test-drive retirement early
Model scenarios that let you experience elements of retirement before fully stepping away.
What Coast FIRE could actually change in real life
Coast FIRE is not the same as being ready to retire today. It asks a more specific question: could your current invested pot grow towards your future retirement target without needing heavy extra contributions? These examples show how different people might use that result to rethink work, saving and lifestyle choices.
Nadia, moving towards a four-day week
Age 40 • Target retirement age 60 • Wants £30,000 a year
Nadia has been saving hard through her 30s and now wants to reduce the pressure. She is not trying to retire yet. She wants to know whether her existing pension, ISA and GIA could keep growing towards her future retirement target if she stopped making large extra contributions.
- She keeps automatic workplace pension contributions running.
- She pauses extra retirement top-ups for now.
- She uses a separate household budget check before changing her working week.
What Nadia does next
Nadia sees that her current invested pot is above the estimated Coast FIRE number. The calculator does not prove she can afford a four-day salary today, but it does suggest her retirement saving may no longer need to be as aggressive. Her next step is to check day-to-day cashflow separately before asking about a four-day week.
Owen, building a consultancy runway
Age 45 • Target retirement age 62 • Wants £36,000 a year
Owen has a demanding management job and wants to move into consultancy over time. He does not want to damage his long-term retirement plan, so he checks how close he is to Coast FIRE before reducing his pension saving or stepping away from full-time employment.
- He keeps saving around £1,500 a month for another two years.
- He builds consultancy clients while still employed.
- He reassesses once the gap to Coast FIRE has narrowed or closed.
What Owen does next
Owen sees that he is still around £35,000 short of his estimated Coast FIRE number. Rather than treating Coast FIRE as permission to leave immediately, he uses it as a milestone. He keeps his current saving pace for another 18 to 24 months while testing whether the consultancy can become reliable income.
Meera and Tom, redirecting some savings
Ages 50 and 49 • Target retirement age 65 • Want £42,000 household income
Meera and Tom have spent a decade overpaying pensions and ISAs. Their children are getting older, and they want more money available for family travel and school-holiday flexibility without losing sight of retirement.
- They reduce extra retirement top-ups from £2,000 to £500 a month.
- They keep regular pension saving in place rather than stopping completely.
- They separately check how much can be redirected into travel and family time.
What Meera and Tom do next
Meera and Tom see that their current invested pot is above the estimated Coast FIRE number. The calculator does not tell them how much holiday spending is affordable today, but it does show they may not need to keep saving at the same intensity for retirement. They use that result as a prompt to reduce extra top-ups and review their household budget separately.
What is the Coast FIRE Calculator
The Coast FIRE Calculator estimates how much you’d need invested today for your portfolio to grow to your desired retirement income level by your target retirement age, assuming no further contributions. It also shows how your current pensions, ISAs and GIAs compare to that Coast FIRE number.
What is Coast FIRE?
Coast FIRE is a stage on the financial independence journey where you’ve already built enough invested wealth that, if left to grow, it should reach your retirement target without any further contributions. From that point on, you only need to earn enough to cover your current living costs, rather than continuing to save heavily for retirement.
How does it work?
The tool takes your current age, target retirement age, desired retirement income, withdrawal rate, and growth assumptions. It then works backwards to find the starting pot required today so that, with compound growth, it can reach the value needed to support your planned retirement income. Your current investments are then measured against that target.
What information do I need to use the tool?
You’ll need:
- Your current age
- Your target retirement age
- Your desired annual retirement income
- Your current pension, ISA and GIA balances
- Your assumed long-term investment growth rate
- Your chosen safe withdrawal rate
- Whether you want to include the State Pension, and from what age
The more realistic your inputs, the more useful the results.
Does this calculator include the State Pension?
Yes. You can choose whether to include it and at what age. Including the State Pension will often reduce the pot size required for Fat FIRE or Lean FIRE later in life.
Is Coast FIRE the same as full FIRE?
No. Full FIRE means you can stop working entirely, and your investments cover all your living costs right now. Coast FIRE means you’ve built enough for retirement later, but in the meantime, you still need to work (often in a more relaxed or enjoyable role) to cover current living expenses.
How accurate are the results?
The results are estimates based on your assumptions. Actual investment returns, inflation and life events will vary. The calculator is best used as a planning tool to understand rough targets and trade-offs, not as a guarantee.
What growth rate should I use?
That’s a personal choice and not a prediction. Many people use a conservative real (after-inflation) return or a nominal return with inflation in mind. You can try a range of growth rates to see how optimistic or cautious assumptions affect your Coast FIRE number.
Is my information saved or stored?
No. All calculations run in your browser. We do not store, transfer or retain any personal data.
Can this replace a financial adviser?
No. This tool provides a reliable benchmark and planning framework, but it cannot account for the full complexity of your financial situation. For personalised advice, speak to a qualified financial adviser
Trust and education
Certified Money First Aider®
These calculators are built by a Certified Money First Aider to help you think more clearly about money and time. Money First Aid® is about practical, non-judgemental support for financial wellbeing. The calculators can certainly help you make informed decisions, but they are not regulated financial advice.
