Investment Return Calculator
See how an investment can grow over time. Enter a starting amount, a monthly contribution, the expected annual return and inflation to get the future balance in nominal terms and in today's money, with a yearly chart and table.
The annual return is treated as an effective yearly rate and compounded monthly at (1 + r)1/12 − 1. Real values are in today's money after inflation.
Growth timeline
| Year | Contributions | Growth | Total contributed | Balance | Real balance |
|---|
Estimates only, not financial advice. Real returns vary from year to year and can be negative. Fees and taxes are not included.
How to use the Investment Return Calculator
- Enter the initial investment and how much you will add each month.
- Choose the timing: start-of-month contributions get one extra month of growth each time.
- Set the number of years, the expected annual return and the inflation rate.
- Optionally raise contributions each year, for example by 3% to match pay rises.
- Press Calculate and compare the nominal balance with the real value in today's money in the chart and the yearly table.
Investment growth formulas
- Monthly rate i = (1 + annual return)1/12 − 1
- End-of-month contributions: balance = balance × (1 + i) + contribution, every month
- Start-of-month contributions: balance = (balance + contribution) × (1 + i)
- Lump sum only: future value = initial × (1 + annual return)years
- Real value = nominal balance ÷ (1 + inflation)years
- Real return = (1 + return) ÷ (1 + inflation) − 1
Example projections at 7% return and 3% inflation
| Plan | Years | Total contributed | Nominal balance | Real value |
|---|---|---|---|---|
| $10,000 lump sum | 20 | $10,000 | $38,696.84 | $21,425.50 |
| $10,000 + $500 a month | 10 | $70,000 | $105,197.38 | $78,276.73 |
| $500 a month | 20 | $120,000 | $253,768.19 | $140,505.29 |
| $300 a month | 30 | $108,000 | $350,835.78 | $144,539.70 |
Contributions are made at the end of each month. The longer the time frame, the larger the share of the final balance that comes from growth rather than from your deposits.
Tips for realistic projections
- Run a low, middle and high return case instead of relying on one number.
- Subtract fund fees from the return. A 1% fee over 30 years can take a large share of the final balance.
- Look at the real value. It tells you what the money will actually buy.
- Markets do not grow in a straight line. Actual balances will move up and down around the projection.
Frequently asked questions
How is investment growth calculated?
Each month the balance grows by the monthly rate, (1 + annual return)^(1/12) − 1, and your contribution is added at the start or end of the month. With no contributions, this gives exactly initial × (1 + return)^years.
What is the difference between nominal and real value?
The nominal balance is the number of dollars you will have. The real value divides it by (1 + inflation)^years to show what it would buy in today's prices. With 7% growth and 3% inflation, the real return is about 3.88% a year.
What annual return should I use?
There is no guaranteed number. Broad US stock indexes have returned roughly 10% a year before inflation over long periods, but with large swings, and bonds and cash return less. Many people test a cautious 5% to 7% and compare several cases.
Does contributing at the start of the month matter?
A little. Money added at the start of each month earns one extra month of growth. Over 10 years with $500 a month at 7%, it adds about $480 compared with end-of-month contributions.
Is CAGR the same as the annual return here?
Yes for a single lump sum: the annual return you enter is the compound annual growth rate (CAGR) of the investment. With regular contributions, your money-weighted return equals the same rate because every dollar grows at it.
Are fees and taxes included?
No. Subtract fund fees from the expected return (for example 7% − 0.2%) to include them. Results are estimates only, not financial advice.