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Investment Calculator: Growth After Fees and Inflation
Enter what you invest, how much you add, an assumed yearly return, an annual fee and an inflation rate. See the projected value, the fee drag and what the result may be worth in today's purchasing power.
What the projection does
The calculator subtracts the annual fee from your assumed return to get a net yearly rate, converts it to an equivalent monthly rate with (1 + net)1/12 − 1, and rolls the balance forward month by month: grow the balance, then add that month's contribution. If you set a yearly increase, the contribution is raised by that percentage at the start of each new year.
The inflation-adjusted figure divides the final value by (1 + inflation)years. It answers a different question from the headline: roughly how much shopping power the future amount holds compared with today.
Why small fees matter
A fee is charged every year on the whole balance, so it compounds against you just as returns compound for you. A difference of one percentage point looks tiny in a single year but can remove a noticeable slice of the final pot after two or three decades. The "cost of fees" row shows that gap in money terms. Include every ongoing charge you pay: fund expense ratios, platform fees and advice fees.
Choosing assumptions responsibly
- Run several scenarios: a lower return, your central case and a higher one. A single number gives false precision.
- Keep return and inflation on the same basis. If you enter a return before inflation, read the inflation-adjusted line for planning.
- Do not extrapolate a recent strong year. Long-run returns differ by asset, country and period, and past performance does not predict the future.
What is left out
Taxes, currency movements, withdrawals, one-off deposits and sequence-of-returns risk are not modelled. A real portfolio can lose value, and losses early on hurt more than the smooth average suggests. This is an illustration of arithmetic and is not investment advice. For a plain lump sum, the future value calculator is simpler.
Using the result in a plan
Treat the projection as a range check against a goal, not a target date. Compare the end value with what you need, then test whether raising contributions by a small amount, or extending the period by a few years, closes any gap more reliably than hoping for a higher return. Revisit the numbers once a year because income, costs and goals change. Keep an emergency fund outside your investments so you are not forced to sell after a fall.
Worked example
An investor starts with 5,000, adds 250 a month for 25 years, assumes 6.5% a year before a 0.75% annual cost, and expects 3% inflation.
Inputs
| Starting amount | 5000 |
|---|---|
| Monthly contribution | 250 |
| Yearly increase in contribution | 0 % |
| Assumed annual return before fees | 6.5 % |
| Annual fees and costs | 0.75 % |
| Assumed inflation | 3 % |
| Years invested | 25 |
Result
About 87,539.72 in today's purchasing power at 3% inflation.
| Total you invest | 80,000.00 |
|---|---|
| Growth after fees | 103,288.73 |
| Net return used | 5.75% a year |
| Value with no fees | 206,004.78 |
| Cost of fees over the period | 22,716.05 |
- Contributions are added at the end of each month. Returns are smooth every year; real markets move up and down.
Financial disclaimer: Results are estimates for planning and education. They are not financial, tax or legal advice. Fees, taxes, rates and rules vary by lender, product and country, so confirm figures with your provider or a qualified adviser before making decisions.
Frequently asked questions
What return should I assume?
There is no correct figure. Use a cautious value, test a lower one, and remember that the actual path will be uneven. This tool treats the number you enter as an assumption only.
How is the inflation-adjusted value worked out?
The final amount is divided by one plus the inflation rate raised to the number of years. It shows the future sum in terms of today's purchasing power.
Are fees taken from the return or the balance?
Here the fee percentage is subtracted from the yearly return, which is a close approximation of a charge applied to the balance.
Why are my contributions added at the month end?
It is a common simplification. A deposit at the start of the month would add a little more interest.
Does this include tax?
No. Tax rules differ by country and account type, so enter a lower return if you want a rough allowance.
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References and sources
- Investor.gov (U.S. SEC): guidance on fees, expenses and compound growth. Link
- Standard time-value-of-money texts: growth of a level and a growing contribution stream.