How the millionaire calculator works

This calculator answers two questions: how much you would need to save each month to reach your target — £1,000,000 by default — within a chosen number of years, and how long it would take at the monthly amount you can actually afford. Both factor in your current savings and a chosen rate of growth.

It is a motivating way to see the power of consistent saving and compounding. Turning the plan into reality is easier with a tax-efficient strategy — something we are happy to help with.

The two things that decide the outcome

Time and rate, and time does far more of the work than people expect. Money invested early compounds on everything that follows it, which is why a smaller amount started ten years sooner routinely beats a larger amount started later. The arithmetic is unintuitive and it is the whole argument for starting badly rather than waiting to start well.

Real returns, and the tax wrapper

A projection in today's money is more honest than one in future money, because inflation erodes the target as well as the contributions. And where the money sits changes the outcome substantially: an ISA is free of income tax and capital gains tax, a pension adds tax relief on the way in and is taxed on the way out, and neither is right for everyone.

Charges compound in the same direction as returns. A percentage point of annual fee sounds small and is not over decades.