Investment Calculator
Project how regular monthly investing plus an expected return builds wealth over time.
Last reviewed July 1, 2026
Projection only. Real returns vary and can be negative in any given year.
Consistent investing beats big one-off deposits for most people, because regular contributions ride out market ups and downs and give compounding decades to work. This investment calculator projects the future value of a portfolio you build up with a monthly contribution and an optional starting balance.
Choose an expected annual return and a time horizon to see the projected total, how much of it is your own money, and how much is investment growth. It's the fastest way to answer 'if I invest X a month, what could I have in 20 years?'
Why regular investing works
Investing a fixed amount every month is often called dollar-cost (or pound-cost) averaging. You automatically buy more units when prices are low and fewer when they're high, which smooths out your average purchase price and removes the temptation to time the market.
Because each contribution has its own runway to compound, money invested early does the most work. Increasing your monthly amount even slightly, or starting a few years sooner, has an outsized effect on the final figure.
Choosing a realistic return
Historically, broad global stock markets have returned roughly 6–8% a year on average over the long run before inflation — but with significant swings, including multi-year downturns. Bonds and cash return less. A diversified portfolio sits somewhere in between depending on your mix.
For planning, it's wise to use a conservative rate and treat the output as a projection, not a promise. Real returns (after inflation) are what determine future buying power, so consider running the numbers with a lower 'real' rate too.
Frequently asked questions
▶How much should I invest each month?
Enough to hit your goals without straining your budget or emergency fund. Many people aim for 10–20% of income, but the right number depends on your timeline and targets. Try a few amounts here to see the impact.
▶Is a 7% return guaranteed?
No. Investment returns vary year to year and can be negative. Long-run stock market averages have been in the high single digits before inflation, but the future is uncertain — use conservative assumptions.
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Open calculator →Disclaimer: Investment Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.