How Long Will My Money Last?

How this calculator works

This is a drawdown model. It starts with your pot and walks forward one month at a time. Each month it grows the balance by your expected return, subtracts what you spend, and adds any ongoing income such as a pension. Once a year it lifts your spending by the inflation rate, because the same lifestyle costs a little more every year. It keeps going until the balance reaches zero, and that point is your run-out date. If your income and returns keep pace with your rising spending, the pot lasts the full 60 years modelled and you’ll see a 40-plus-year result instead.

Four inputs move the answer the most: the size of your pot, your monthly spending, the return you earn, and the inflation rate you assume. Small changes compound, so it’s worth testing a few scenarios rather than trusting a single number.

The 4% rule explained

The 4% rule is the best-known shortcut for retirement spending. The idea: withdraw 4% of your starting pot in the first year, then adjust that pound amount for inflation each year after. Historically that withdrawal rate let a mixed portfolio last around 30 years. On a £500,000 pot, 4% is £20,000 a year, or roughly £1,667 a month.

Treat it as a starting point, not a promise. It came from historical US market data, assumes a particular mix of shares and bonds, and doesn’t know your retirement will be shorter or longer than average. If you’re retiring early or want more of a safety margin, a lower rate of 3 to 3.5% is more cautious. The calculator above lets you test what any spending level does to your run-out date.

Understanding the inflation presets

Inflation is the input people underestimate most, so this tool gives you three framings rather than one guessed number:

• Low, the central-bank target or long-run average. What inflation looks like in calm years.
• Moderate, closer to the current headline CPI. A sensible middle assumption for planning.
• High (lived), an essentials-weighted rate. Housing, food and energy tend to rise faster than the headline basket, so retirees often feel a higher personal inflation than the published figure.

These are illustrative assumptions, not forecasts. Inflation moves, and it varies by country, so check the current CPI for your region before you rely on any single figure. The region selector sets sensible defaults, but you can always type a custom rate.

How to use this calculator

1. Pick your region, it sets the currency, the income label (State Pension, Age Pension, Social Security or Pension) and sensible inflation defaults.
2. Enter your current savings pot. In Australia, only include super if you can already access it, it's locked until preservation age.
3. Enter your monthly spending today, in current money.
4. Set an expected annual return for the pot while it's invested, then choose an inflation preset or type a custom rate.
5. Add any ongoing monthly income such as a pension, then read how many years and months your money lasts.

Frequently asked questions

This calculator is an estimate to help you think, not financial advice. It gives a pre-tax figure and can’t know your personal circumstances. For decisions about your retirement, speak to a qualified financial adviser.