From 833 a month over 10 years to 243 over 20 years at 5%: what time and returns change.
Key findings
- With no return, 100,000 means 833.33 a month over 10 years and 416.67 over 20.
- At 5% a year, 243.29 a month is enough over 20 years: you put in 58,389 and the rest is growth.
- Time matters more than return: starting earlier cuts the effort a lot.
The sum without any return
To save 100,000 without your money earning anything, just divide: 100,000 by the number of months you have. Over 10 years that is 833.33 a month; over 15 years, 555.56; over 20 years, 416.67. It is the most cautious benchmark, because it does not depend on any market.
What a return changes
If the money you set aside earns something, you need to put in less each month, because the returns do part of the work. These are hypothetical figures, with a constant annual return and before tax:
| Time frame | No return | At 3% a year | At 5% a year |
|---|---|---|---|
| 10 years | 833.33 | 715.61 | 643.99 |
| 15 years | 555.56 | 440.58 | 374.13 |
| 20 years | 416.67 | 304.60 | 243.29 |
Time matters more than the return. Over 20 years at 5%, putting in 243.29 a month means 58,389 comes out of your pocket and the other 41,611 is investment growth. Over 10 years, the return helps much less because it has less time to compound.
Three things to bear in mind
- Returns are not guaranteed. A savings account may pay a fixed rate; the stock market rises and falls. If you count on 5% and get less, you will need to save more or wait longer.
- Inflation. 100,000 in 20 years will buy less than it does today. If your goal is to buy something specific, think about what it will cost then, or use a return after inflation.
- Tax and fees reduce what you earn. The figures on this page are before tax.
How to get started
The most effective way is to automate it: a transfer on payday, before you spend. If the figure looks impossible, start smaller and raise it every time your pay goes up; time will do the rest. And before investing for the long term, build an emergency fund so you never have to sell at a bad moment.
Work out your own case with the savings goal calculator, or see how a monthly contribution grows with the compound interest calculator.