How the FIRE Calculator works

This FIRE calculator estimates the total amount of money you’ll need invested to reach financial independence (your FIRE number), and the age at which this could be achievable given your current level of savings and estimated cost of living in retirement.

You should enter:

  • Current age – in years and months
  • Current savings – the amount you already have saved/invested
  • Yearly savings – the amount you can save each year
  • Required retirement income – the amount you estimate your annual retirement costs to be
  • Estimated annual growth – your expected rate of return on your investments
  • Safe drawdown rate – typically 4%

The safe drawdown rate (or safe withdrawal rate) is the rate that allows you to withdraw a percentage of your invested money each year, which will cover your costs during retirement. It is typical to use a rate of 4% in the US, whereas those in the UK could use a slightly lower rate of 2.5 or 3%.

The target Fire number is calculated by dividing your annual retirement costs by your safe withdrawal rate.

The calculator does not account for tax, or pension schemes but is designed to give a simple indication of your target FIRE number and when FIRE can be achieved. You can play around with the numbers to see how saving more or less will affect the Retirement Age. 

Reaching your FIRE number should mean you have enough money invested that the returns on your investments will be enough to cover your living costs once retired.