No account needed. Enter seven numbers — your current age, annual spending in retirement, current savings, monthly savings amount, expected investment growth rate, inflation rate, and safe withdrawal rate — and get an instant answer: when can you retire, and how much do you need?

Your FIRE number is the portfolio value at which your investments generate enough passive income to cover your lifestyle indefinitely at your chosen withdrawal rate. The tool applies inflation separately from your growth rate, so your results are in today's money rather than nominal future values.

Use this to get a feel for the ballpark before committing to a full profile.

The Calculator tab is your complete financial model. It separates your wealth into three pots — taxable investments, tax-free (ISA/Roth), and DC pension — and applies the correct tax treatment to each when projecting withdrawals in retirement.

Key inputs to fill in:

• Personal: current age, target retirement age, country (sets your tax regime)
• Portfolio: current balance in each pot (taxable, ISA/tax-free, DC pension), monthly contributions
• Income: expected annual retirement spending, DC and defined benefit (DB) pension details, state/social pension age and amount
• Assumptions: nominal investment growth rate (7% is a common long-run estimate for a diversified equity portfolio before inflation), inflation rate (2.5% default, applied separately to get real purchasing power), safe withdrawal rate (4% is the widely-cited starting point), life expectancy
• Asset allocation: optionally set a stocks/bonds split — the tool uses this to blend growth rates when running simulations

FIRE type: choose Standard (full retirement), Barista FIRE (part-time work covers some expenses), or Semi-FIRE (ongoing income for a set period). Each adjusts the portfolio withdrawal required during that phase.

Try a Scenario: the Calculator tab includes preset example profiles (e.g. UK professional, US early retiree) that pre-fill sensible defaults — a quick way to explore how the tool works before entering your own numbers.

The deterministic projection gives you a single straight-line forecast — useful as a baseline reference point, but it assumes markets grow smoothly every year, which they never do. That's what the Pro tools are for.

Your data auto-saves every few seconds. Use Save Scenario to create named snapshots — ideal for comparing "retire at 50 with lean spending" vs "retire at 55 with more comfort".

Auto-save: your current inputs are written to the cloud automatically while you're signed in — you'll never lose your work.

Named scenarios: save multiple named snapshots of your inputs (e.g. "Base case", "Optimistic", "What if I stop contributing at 45"). Load any scenario from the Save/Load button to switch between them instantly.

Export to JSON: download a full backup of your inputs to your device. Useful for sharing with a financial adviser or archiving a point-in-time snapshot.

Import: restore any previously exported JSON file.

Excel export (Pro): export your full year-by-year projection data to a spreadsheet for deeper offline analysis.

Select your country in the Calculator and all projections — deterministic, Monte Carlo, and backtests — use the correct tax rules for your situation:

• 🇬🇧 United Kingdom: income tax bands, personal allowance taper (£100k–£125,140 at 60% effective marginal rate), CGT rates (post-Oct 2024: 18%/24%), SIPP 25% UFPLS tax-free element, ISA as tax-free pot
• 🇺🇸 United States: federal income tax brackets, long-term capital gains rates (0%/15%/20%), 401(k) as ordinary income, Roth as tax-free
• 🇨🇦 Canada: federal income tax, 50% capital gains inclusion rate, RRSP as ordinary income, TFSA as tax-free
• 🇦🇺 Australia: income tax, 50% CGT discount for assets held over 12 months, superannuation as tax-free after 60

The single most important tool for validating a retirement plan. Instead of assuming markets grow smoothly at 7% every year, Monte Carlo runs 10,000 different random market sequences using your growth and volatility assumptions, then counts how many of them result in your portfolio surviving to your life expectancy.

Why it matters: a plan that looks fine on a straight-line projection can fail 30% of the time if you retire into a bad sequence of returns. The first decade of retirement is the most dangerous — a market crash early on permanently impairs the portfolio's ability to recover.

What to aim for: 85%+ success rate is generally considered robust. Below 75% means your plan has meaningful shortfall risk and you should consider retiring later, spending less, or building a larger buffer.

The simulation models withdrawals from all three pots in the correct order (taxable first, then pension, then tax-free) with full tax calculations at each step.

Monte Carlo uses synthetic random returns. Backtesting uses real historical market data — it replays your exact withdrawal plan as if you had retired at the start of each of five major crises and asks: would you have run out of money?

The five scenarios tested:

• 2008 Global Financial Crisis — S&P 500 fell ~56% peak-to-trough
• 2000–2002 Dot-com bust — tech-heavy portfolios fell ~78%
• 1970s stagflation — a decade of high inflation and stagnant growth
• COVID-19 crash (2020) — fast, sharp crash followed by rapid recovery
• 1929 Great Depression — the worst-case historical stress test

Surviving 2008 and the dot-com bust gives reasonable confidence. Surviving the 1929 depression is the gold standard for ultra-conservative planning. The 1970s scenario is the most relevant for anyone worried about inflation eroding purchasing power.

Most early retirees face a gap: they want to stop working at 45 or 50, but their pension is locked until 57 (UK minimum access age from 2028; currently 55) or 59½ (US), and their state pension doesn't arrive until 66–67 (UK, rising to 67 between 2026–2028) or 62–67 (US, depending on birth year). The bridge strategy analyses whether your non-pension assets can sustain your lifestyle across all three phases.

The three phases modelled:

• Phase 1 — Early retirement to pension access: living entirely from taxable and ISA/tax-free pots
• Phase 2 — Pension access to state pension: drawing from all pots including DC pension (25% tax-free element applied)
• Phase 3 — State pension age onwards: state/social pension supplements withdrawals, reducing portfolio drawdown

The tool tells you the exact bridge fund size required and flags if Phase 1 would exhaust your accessible assets before your pension unlocks — the most common shortfall scenario for early retirees.

A year-by-year breakdown of your projected cash flows in retirement — showing exactly how much you're drawing from each pot, what tax you're paying, and how your portfolio balance evolves over time.

This makes it easy to spot problems that aggregate numbers hide: for example, a plan where the taxable pot runs dry at age 62, forcing large pension withdrawals that push you into a higher tax bracket for the rest of retirement.

Use it alongside Monte Carlo — the spending view shows the expected path, while Monte Carlo quantifies the risk around that path.

Real financial plans aren't smooth. Add one-off events at specific ages to model how they shift your FIRE date:

• Buying a home (large one-off outflow)
• Inheritance or property sale (windfall inflow)
• Career break or sabbatical (reduced contributions for a period)
• Children's university costs
• Part-time or semi-retirement income (additional earnings that reduce the amount drawn from the portfolio)

Each event is incorporated into all projections — deterministic, Monte Carlo, and backtests — so you see the full downstream impact rather than just an isolated number.

Shows how your marginal tax rate evolves year by year in retirement based on your withdrawal sequence, and identifies opportunities to reduce your lifetime tax bill.

Common optimisations it surfaces:

• UK: staying below the personal allowance taper (£100k) to avoid the 60% effective marginal rate; drawing pension income below the basic rate band
• US: Roth conversion ladders in low-income years; harvesting long-term capital gains at 0% in the 10%/12% brackets
• General: sequencing withdrawals across pots to minimise total tax across a 30+ year retirement

After running any Pro calculation, Ultra subscribers can generate an AI analysis of that specific result. The AI has full context: your inputs, Monte Carlo success rate, backtest outcomes, tax profile, bridge viability, and spending trajectory.

What it provides:

• Plain-English summary of what your results actually mean
• Risk identification — the two or three factors most likely to derail your plan
• Concrete optimisations — contribution changes, withdrawal sequencing, pot allocation tweaks
• Scenario commentary — what happens if growth is 1% lower, or you retire two years earlier

The AI tab provides an open-ended chat interface where you can ask anything about your plan. All responses are generated from your actual data, not generic advice.

AI analysis is not financial advice. Always consult a qualified adviser before making major financial decisions.