How much do I need to retire?

There's no single number — and anyone who hands you one without asking about your life is guessing. Your retirement number depends on three things you actually control: how much you spend, how long you'll need it to last, and what your money earns along the way.

The starting point: the 4% rule

The most-cited rule of thumb is simple. Take your expected annual spending in retirement and multiply by 25. That's a portfolio from which you could withdraw roughly 4% a year, adjusted for inflation, with a strong historical chance of it lasting around 30 years.

• Spend $40,000/year → target ~$1,000,000
• Spend $60,000/year → target ~$1,500,000
• Spend $80,000/year → target ~$2,000,000

It's a useful anchor. It's also incomplete.

Why the rule of thumb breaks down

The 4% rule assumes a fixed 30-year horizon, steady spending and average market behaviour. Real retirements aren't average:

• You might retire early — a 45-year retirement needs a lower withdrawal rate than a 30-year one.
• Spending isn't flat — it's often higher early (travel), lower mid, higher late (care).
• Markets aren't average — a downturn in your first few years of retirement ("sequence-of-returns risk") does far more damage than the same downturn later.
• Other income exists — a pension, state benefits, rental income or part-time work all lower the number your portfolio has to carry.

A single multiplier can't see any of this. A projection can.

The better question: "Am I on track?"

Instead of chasing one magic figure, model the path. Lay out your income, savings rate and expected returns year by year from today to your life expectancy, and watch where your net worth lands. Then adjust the levers — save a little more, retire a year later, spend a little less — and see the effect immediately.

That's exactly what Dispono is built to do: it projects your cashflow and net worth for decades ahead, scores your progress against benchmarks, and lets you stress-test a bad market or an early retirement before you commit to either.