Calculate Investment Growth
Compound interest is the most powerful force in personal finance. Starting early and contributing regularly makes a dramatic difference over time — Irreva's calculator shows you the numbers.
Key inputs
- Initial investment (lump sum) — what you start with
- Monthly contributions — regular additions accelerate growth significantly
- Annual return rate — global stocks have averaged ~7–10% historically (before inflation)
- Time horizon — the single biggest factor in final value
The power of starting early
Investing £200/month at 7% return: starting at 25 yields ~£525K at 65. Starting at 35 yields ~£244K. Ten extra years roughly doubles the outcome — that's compound interest at work.
Frequently Asked Questions
What return rate should I use?
7% is a common real-return assumption for diversified global equities (after inflation). Be conservative — actual returns vary year to year.
Does the calculator account for inflation?
No. Use 4–5% as a return rate to approximate real (inflation-adjusted) purchasing power.