About the Investment Calculator
Investing works through compounding: your gains earn their own gains over time. This investment calculator projects that growth for a starting amount plus regular monthly contributions. Enter the amount you start with, what you add each month, the yearly return you expect and the number of years. You choose how often returns are added and whether contributions go in at the start or the end of each month. The result shows the final value, how much you contributed, how much came from investment gains and what the total would be worth in today's money after inflation. It is an illustration with a steady rate, not a prediction.
Updated October 2026
How to use the Investment Calculator
- 1Enter your starting amount and monthly contribution.
- 2Enter the expected yearly return and the number of years.
- 3Choose compounding frequency and contribution timing.
- 4Enter an inflation rate to see today's money.
- 5Read the final value, contributions and gains.
Worked example
Starting with 10,000 and adding 500 a month at 7 percent for 20 years grows to about 300,850. The contributions total 130,000, so gains are about 170,850, or 57 percent of the total. Waiting five years to start, so the same plan runs 15 years, would give roughly 114,000 less, about 187,000 in total. After inflation at 2.5 percent, the 20-year result is about 183,600 in today's money.
Be realistic about risk when you choose the return. A portfolio made mostly of shares can fall 30 percent or more in a bad year, while cash and bonds are steadier but usually grow more slowly. If you will need the money in less than five years, a lower assumed return, such as 3 or 4 percent, is more honest. For goals decades away, many people accept more volatility in exchange for higher expected growth, and reduce risk as they approach the date they need the money.
Contributions matter as much as the return. Raising your monthly amount by just 100 in this example, from 500 to 600, adds about 52,000 to the final value over 20 years. Increasing contributions each year as your pay rises is one of the simplest ways to hit a target. The calculator keeps contributions level, so if you plan to increase them, run it in stages: once for the first few years, and again with the new balance as the starting amount.
Habits that help
- Start early: time matters more than amount.
- Invest regularly regardless of market news.
- Keep fees low with broad index funds.
- Rebalance occasionally.
- Do not invest money you need within five years.
How to use the results
Work backwards from a goal. If you want 500,000 in today's money in 25 years, try different monthly amounts until the real value matches. Compare optimistic and cautious returns to see the range. Revisit every year, and adjust for changes in income and goals. Remember that real life is bumpier than a straight line.
Related tools
The Savings Calculator suits low-risk accounts, the Compound Interest Calculator gives another view, the CAGR Calculator measures past growth, the SIP Calculator models monthly plans in India, and the Inflation Calculator explains real value.
Features
- Starting amount plus monthly contributions
- Gains and contributions shown separately
- Value in today's money
- Choice of compounding and timing
- Milestone values every few years
- Any currency
Frequently asked questions
How much will my investment be worth?
With 10,000 invested, 500 added every month and a steady 7 percent return, the value after 20 years is about 300,850. You put in 130,000 and the other 170,850 is investment growth. After 2.5 percent inflation that is worth about 183,600 in today's money.
What return should I assume?
Long-run stock market averages have often been quoted at 6 to 10 percent before inflation, while bonds and cash earn less. Returns are uneven and never guaranteed. A lower, cautious figure is wiser for planning.
What is compounding?
Earning returns on your earlier returns. Over long periods it is the main driver of growth: in the example above, gains make up more than half of the final value.
Does it include fees and taxes?
No. Fund fees, platform charges and taxes lower your real return. Subtract them from the rate you enter. A fee of 1 percent a year can reduce a 20-year result by about an eighth: 264,000 instead of 300,850 in the example.
Why show today's money?
Because prices rise. A sum in 20 years will buy less than the same sum today. Dividing by the inflation factor shows the result in terms of current purchasing power.
Can the investment lose money?
Yes. Real returns vary year to year and can be negative. A steady-rate model hides that. For long goals, consider a mix of assets and keep short-term money in safer places.