UK Fin Lab

Professional-grade UK financial tools

NHS Take Home Pay Calculator
Calculated at ukfinlab.co.uk
UK Fin Lab
Professional-grade UK financial tools

FINANCIAL INDEPENDENCE

FIRE Calculator UK

Estimate your FIRE number, projected FIRE age, Coast FIRE, Lean FIRE, emergency fund progress, net worth path and Monte Carlo success rate.

Build your FIRE plan

Enter your income, expenses, pensions, investment strategy, property and debts. The calculator estimates your FIRE number, FIRE age and retirement success range.

Defined contribution pension

Defined benefit pension

Enter your current accrued DB pension as an annual income amount. For schemes like the NHS 2015 scheme, enter your pensionable salary and 54 as the accrual denominator. If your scheme gives a fixed yearly accrual, use the custom annual accrual box instead.

Example: enter 54 for a 1/54th salary accrual.

Optional. If entered, this overrides salary ÷ accrual denominator.

State Pension

The default annual amount is the full new State Pension for 2026/27 (£241.30 per week annualised). Replace this with your own forecast where possible.

Leave as £0 if you want property equity shown in net worth but not counted as spendable FIRE capital.

Other debts

NEXT STEPS

Useful calculators after checking your FIRE plan

FIRE planning combines income, expenses, pensions, investments, debt, inflation and retirement income. These tools can help you refine individual parts of the calculation.

Pensions

Pension Calculator

Project pension growth from contributions, employer additions and investment assumptions.

 Tax-free investing

ISA Calculator

Estimate how ISA savings or investments could grow towards financial independence.

 Scenario modelling

Advanced Compound Interest Calculator

Model changing deposits, withdrawals and growth rates over time.

 Income

Take Home Pay Calculator

Estimate net pay and saving capacity before setting your FIRE contribution plan.

 Income growth

Pay Rise Calculator

See how pay increases could improve your monthly investing and FIRE timeline.

 Debt

Credit Card Payoff Calculator

Compare debt repayment timelines and the impact of debt on your FIRE milestones.

FIRE Calculator UK

This FIRE calculator UK estimates how much you may need invested to become financially independent and whether your current savings, investments, pensions and debt plan are on track. FIRE stands for financial independence, retire early. The goal is to build enough assets that your portfolio and guaranteed retirement income can cover your spending without relying on work.

What this FIRE calculator includes

  • Monthly take-home income, extra income and expected income increases
  • Current expenses, target retirement expenses and inflation assumptions
  • Current investments, regular investing, cash savings and emergency fund checks
  • Defined contribution pension pot, employee contributions, employer contributions, growth and fees
  • Defined benefit pension income, start age and indexation
  • State Pension amount and start age, with the full new State Pension as the default
  • Property value, mortgage balance, expected house-price growth and optional property release/downsize capital
  • Debt balance, interest and monthly repayment assumptions
  • Safe, moderate, risky and custom investment strategy assumptions
  • FIRE number, Lean FIRE, Coast FIRE, FIRE age, net worth chart and 1,000-run Monte Carlo simulation

How the FIRE number is calculated

The main FIRE number uses a finite-life calculation. It projects your target retirement spending from your chosen retirement age to life expectancy, subtracts guaranteed income such as State Pension and defined benefit pension income when those payments begin, then estimates the private pot needed to cover the remaining shortfall.

The calculator also shows a safe-withdrawal-rate comparison. This can be useful as a quick benchmark, but it is less personalised than the finite-life calculation because it does not fully account for changing income streams during retirement.

What is Coast FIRE?

Coast FIRE is the point where your current invested pot could grow to your required FIRE number by the target retirement age without further contributions. You may still need to work to cover living costs, but your retirement investing target is theoretically on track.

What is Lean FIRE?

Lean FIRE is a lower-spending version of financial independence. This calculator uses your chosen Lean FIRE percentage of target retirement expenses, so you can test a more frugal retirement target without changing the full FIRE scenario.

What the Monte Carlo simulation means

The Monte Carlo section runs 1,000 simulated investment paths using your chosen expected return and volatility. It estimates the percentage of scenarios where the portfolio lasts to your life expectancy. The result is not a prediction or guarantee, but it helps show how sensitive the plan may be to market volatility.

Important note

This calculator provides estimates only and is not financial, tax, pension, mortgage or legal advice. Investment returns are not guaranteed, pension rules can change, and your own tax position may affect the result.

FIRE calculator FAQs

Yes. It includes an editable State Pension amount and start age. The default is the full new State Pension annualised from the 2026/27 weekly rate, but you should replace it with your own forecast if you have one.

Yes. The projection tracks non-pension investments and DC pension pots separately. If your target retirement age is before your DC access age, the calculator checks whether your accessible pot can bridge the gap.

House equity is included in the net worth chart. It is not counted as FIRE capital unless you enter a property release/downsize amount, because a home you live in does not automatically pay your retirement expenses.

The 25x rule is a simple safe-withdrawal-rate shortcut. This calculator also models retirement age, life expectancy, inflation, State Pension, defined benefit pensions and pension access timing, so the personalised result may be higher or lower.