The Compounding

The most powerful idea in personal finance, made visible.
Saving and pensions
The narrator

Here is the surprising part. Save just under £40 a month from age 18, and by 67 you reach roughly the same pot as someone who saves £200 a month but only starts at 45. The early starter pays in far less each month, yet time does the heavy lifting. This assumes a steady 5% return every year. Real investment returns rise and fall, and are never guaranteed.

What you'll do

  • Drag three sliders: when you start saving, how much you save each month, when you stop.
  • Watch the chart move in real time. See the total pot grow.
  • Compare yourself against three other savers who started at different ages.
3Sliders
5%Annual growth
~5Minutes

Why this matters

Two students leave school at eighteen. One starts saving £30 a month into a pension. The other waits, plans to start "when there's more money", and gets serious at thirty-five. The first student keeps going until sixty-seven. So does the second. Who has more? Drag the sliders. The answer is not what most people think.

Your savings, over time
Move the sliders. The chart, and the answer, move with you.
1860
£10£500
4070
Your pot at the end
£0
Total paid in: £0
Pot value, over time

You and three other savers

All four people stop saving on the same day, at age 67. They just started at different times.

You
Started at 18
£0
Paid in: £0
Early starter
Saved £30/mo from 18
£0
Paid in: £0
Mid starter
Saved £100/mo from 30
£0
Paid in: £0
Late starter
Saved £250/mo from 45
£0
Paid in: £0
What the chart is telling you

The big idea

When you save money in something that earns a return (a pension, a Stocks and Shares ISA, a long-term savings account), your money earns money. The next year, both the original money and last year's earnings are earning money. Then the year after that, all three are. This is compounding.

It looks slow at first. After ten years, it looks like nothing special is happening. But after thirty or forty years, the line on the chart curves sharply upward. The work is being done by time, not by the amount you pay in. That's why starting at eighteen, even with very little, beats starting at thirty-five with a lot. You can't buy back time.