Investment Growth Calculator
Project how your investment portfolio could grow over time. Enter your initial investment, regular contributions, expected return rate, and time horizon — and see the power of compound returns at work.
Investment details
How the investment growth calculator works
This calculator applies compound growth to your investment inputs, modelling a portfolio that earns a consistent annual return on its growing balance. Enter your initial investment, regular monthly or annual contribution, expected return, and years invested. The results show your projected portfolio value, the total amount you put in, and how much of the ending value is pure investment gains.
Worked example: 25-year investment plan
Scenario: £5,000 initial investment, £250/month contributions, 7% annual return, 25 years.
| Metric | Value |
|---|---|
| Initial investment | £5,000 |
| Total monthly contributions | £75,000 (£250 × 300 months) |
| Total money invested | £80,000 |
| Investment gains (compound growth) | £133,960 |
| Final portfolio value | £213,960 |
| Total return | 167% |
The investment gains — over £133,000 — exceed the total amount invested. This is the long-term effect of compound returns: your money earns more than you put in.
Why regular contributions matter so much
A one-off lump sum benefits from compounding, but consistent monthly contributions have a compounding effect of their own. Each new contribution immediately starts earning returns, and earlier contributions have had longer to grow. This is why even a relatively modest monthly amount, invested consistently for 20–30 years, can build substantial wealth.
This concept is sometimes called dollar-cost averaging when applied to volatile assets — by investing regularly regardless of market price, you buy more units when prices are low and fewer when they're high, smoothing your average entry price over time.
Frequently Asked Questions
Related Calculators & Tools
See how your money grows with compound interest over time.
🎯Find out exactly when you'll reach your savings target.
🔄See the impact of consistent, regular deposits on your wealth.
🏦Estimate your retirement savings balance at any retirement age.
📖Understand how investment returns compound over time.