Coast FIRE is a planning concept, not a finish line. It describes an illustrative point where an existing portfolio may grow to a later target without further contributions, assuming future returns and spending are favourable enough.

Why UK context matters

For many people, the relevant question is not only “when could I stop contributing?” It is also which assets are accessible before pension access age. The ISA rules and pension rules can change, so treat this as a planning prompt rather than a withdrawal plan.

Use conservative assumptions

• Use spending in today’s money.
• Use a real return after inflation and fees, not a headline market return.
• Test a lower return and a lower withdrawal rate.
• Keep a separate view of accessible ISA/cash assets and pension assets.

The result cannot tell you whether you are ready to reduce work, stop investing or take investment risk. It simply shows how sensitive a long-term plan is to time, spending and assumptions.

The accessible-assets bridge

Coast FIRE is not evidence that work can stop today. If the plan relies on pension assets, separately estimate spending between reducing work and pension access. Most registered private pensions cannot normally be accessed before age 57 from 6 April 2028, subject to limited exceptions and protected ages. Check your own scheme, not a generic rule. Your State Pension forecast is also individual, not an assumption this tool can make for you.

Key limitation: this first version does not model tax, benefits, debt, housing changes, care costs, sequence risk or individual pension rules. It is a planning prompt, not evidence that money will last.

Related reading

• Financial Independence
• £1m Path Calculator