Why time can be an investor's greatest ally
One of the most powerful concepts in investing is compound interest.
It simply means earning returns not only on the money you've invested, but also on the returns you've already made. Over time, this can make a significant difference to the value of your investments.
Three things have the greatest influence on long-term investment outcomes: how much you invest, the returns you achieve and how long your money remains invested. Compound interest brings these factors together by allowing your returns to generate further returns over time.
| Year | Principal | Interest @ 5% | Total |
| 1 | £100 | £5 | £105 |
| 2 | £105 | £5.25 | £110.25 |
| 3 | £110.25 | £5.51 | £115.76 |
| 10 | £155.13 | £7.76 | £162.89 |
If interest were earned only on the original £100, a ten-year investment at 5% would grow to £150. With compounding, the same investment grows to almost £163.
The effect becomes much more noticeable when regular contributions are added.
Over the ten years, the investment totals £1,100 (£100 initially, followed by ten annual contributions of £100). With annual growth of 10%, the value has increased to around £2,012.
| Year | Principal | Additional Investment | Growth @ 10% | Total |
| 1 | £100 | £100 | £20 | £220 |
| 2 | £220 | £100 | £32 | £352 |
| 3 | £352 | £100 | £45 | £497 |
| 10 | £1730 | £100 | £183 | £2012 |
These examples highlight one of the biggest advantages investors have: time. The longer your money remains invested, the more opportunity it has to benefit from compound growth. That's why many long-term investors focus less on short-term market movements and more on staying invested.
If you'd like to see the impact for yourself, try using a compound interest calculator to compare different investment amounts, time periods and rates of return.
Key points to remember
Start early
Time is one of the biggest advantages an investor has. The earlier you begin investing, the longer compound interest has to work.
Invest regularly
Regular contributions, even relatively modest ones, can build into a substantial sum over many years. Investing consistently is often more important than trying to invest large amounts all at once.
Small differences matter
Even relatively modest improvements in long-term investment returns can make a significant difference over time. A small increase in annual returns can have a powerful effect over decades.
Think long term
Compound interest rewards patience. The longer your money remains invested, the more opportunity it has to generate returns on previous returns. That's why time is often considered one of an investor's greatest advantages.
Build habits you can maintain
Long-term investing should fit alongside your wider financial goals and lifestyle. The best investment plan is often one you can stick with consistently over time.
The earlier you start and the longer you stay invested, the more opportunity compound interest has to work. You don't need to invest large sums to begin – what matters most is building good investing habits and giving your money time to grow.
One more thing to bear in mind
Inflation reduces what your money can buy over time. This means that even if the value of your investments grows, it's important to consider whether those returns are keeping pace with inflation.
Just as investment returns can compound over time, the effects of inflation can too. That's one reason many people choose to invest rather than relying solely on cash savings for long-term goals.
