Investment Calculator
Use this investment calculator to project how a starting amount and monthly contributions could grow at an assumed annual return. You can raise contributions every year, subtract a fund's expense ratio and adjust for inflation to see the result in today's dollars. The table and chart split your balance into money you put in and investment growth.
Updated
Results
- Total contributedInitial investment plus all contributions
- Investment growthFinal value minus what you put in
- Total fees paid
- Final value in today's dollarsAdjusted for the inflation rate you entered
- Net annual returnReturn after the annual fee
| Year | Total contributed | Total growth | Balance |
|---|
Results are estimates. See the methodology below.
How to use the calculator
- Initial investment: what you invest today. It can be $0 if you only contribute monthly.
- Monthly contribution: the amount you add every month, such as a payroll deduction or automatic transfer.
- Expected annual return: the average yearly return you want to test, before fees.
- Investment period: how many years the money stays invested.
- Advanced options: a yearly increase in your contribution, an annual fee (a fund's expense ratio or an advisory fee) and an inflation rate.
Fees paid and the value in today's dollars appear only when you enter a fee or an inflation rate.
How the calculator works
The simulation runs month by month. The annual return r is converted into a monthly growth factor, so twelve months compound to exactly the rate you entered:
g = (1 + r)^(1/12)
Each month the balance is multiplied by g, then one-twelfth of the annual fee is taken out in the same compounding way, then your contribution is added at the end of the month. After every full year the contribution rises by the increase you set.
- Total contributed includes the initial investment.
- Net annual return = (1 + r) × (1 − fee) − 1.
- Value in today's dollars = final value ÷ (1 + inflation)^years.
The return is applied smoothly every month. Real markets move up and down, and the order of good and bad years affects what you end up with, especially near the end. Taxes, trading costs and withdrawals are not included.
Worked examples
1. $10,000 plus $500 a month for 25 years
At a 7% annual return with no fees, the balance reaches $445,795.27. You contributed $160,000; the other $285,795.27 is growth. Compounding speeds up over time: the balance is $105,197.38 after 10 years and $292,465.03 after 20. With 3% inflation, the final amount is worth about $212,914.30 in today's dollars.
2. How much fees matter
Same plan, with different annual fees:
| Annual fee | Final value | Fees paid |
|---|---|---|
| 0% | $445,795.27 | $0 |
| 0.05% | $442,036.68 | $2,106.23 |
| 1% | $376,943.08 | $37,954.66 |
A 1% fee leaves you $68,852.19 short of the no-fee result, almost twice the fees themselves, because every dollar taken out also stops compounding.
3. Raising contributions 3% a year
Starting from $0 with $500 a month, increased by 3% every year, at 7% for 25 years, you end with $515,895.45 after contributing $218,755.59.
How to read your results
Treat the result as one scenario, not a forecast. Try a cautious, a middle and an optimistic return to see a range. If growth overtakes your contributions only late in the period, starting earlier or contributing more has a bigger effect than chasing a slightly higher return. Comparing the real value with your contributions shows whether your money is likely to keep its purchasing power.
Frequently asked questions
What rate of return should I use?
No return is guaranteed for stocks, bonds or funds, and past performance doesn't predict future results. Test several rates, and use a lower one for a mix that includes bonds or cash. Enter the return before fees and put the expense ratio in the fee field.
Does the calculator include taxes?
No. In a taxable brokerage account, dividends and capital gains can be taxed along the way. A 401(k) or IRA follows its own rules: traditional accounts generally defer tax until withdrawal, and qualified Roth withdrawals can be tax-free. The result here is before any tax.
What is an expense ratio?
It's the annual cost of running a mutual fund or ETF, expressed as a percentage of your investment and deducted from the fund's assets. You'll find it in the fund's prospectus or fact sheet. Advisory or account fees come on top; add them to the fee field to see their combined effect.
Can the calculator show a loss?
Yes. Returns down to −50% a year are accepted. For example, $10,000 at −5% a year for 3 years falls to $8,573.75. A constant negative rate is still a simplification; real losses come in uneven steps.
Why do I get an error when both amounts are zero?
With no initial investment and no monthly contribution there's nothing to grow. Enter a starting amount, a monthly contribution or both.
Sources
This calculator provides estimates for educational purposes only and is not investment or tax advice. Investments can lose value, and actual returns, fees and taxes will differ from these assumptions.