Halftime Financial

Compound Growth Calculator

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The Power of Compound Growth

Einstein called it the "eighth wonder of the world." See exactly how your money multiplies over time — and why starting today matters more than starting perfectly.

3.9×
Your money multiplier
Your Assumptions
Starting lump sum (can be zero)
7.0%
Historical global equities ~7–9% nominal long-run. Adjust for your strategy.
2.5%
Real return = Growth Rate − Inflation.
20 yrs
2.0%
Typically linked to salary growth.
Rule of 72
Years to double your money at 7% return

The Rule of 72: divide 72 by your annual return to estimate how many years it takes for money to double. At 7%, your money doubles every ~10.3 years — and doubles again from there.

Final Value
in 20 years
Real Value (Inflation Adj.)
Today's purchasing power
Total Contributions
Money you put in
Investment Growth
Return on top of contributions
Portfolio Growth Over Time
Where Your Money Comes From
Year-by-Year Summary
YearAnnual Contrib.Growth This YearTotal ContributionsPortfolio ValueReal Value
Educational Tool Only. This calculator provides illustrative projections based on your inputs and assumed constant rates of return. Real investment returns vary, are not guaranteed, and can be negative. This tool does not constitute financial advice under the UK Financial Services and Markets Act 2000 (FSMA) or the South African FAIS Act. Past performance is not a guide to future results. © 2026 Halftime Financial.