How to use the Investment calculator
- Enter your numbers. Fill in starting amount, contribution, every, increase contributions yearly by, expected annual return, years to invest, inflation.
- Read your results. Results update instantly. The headline shows the projected portfolio value; the breakdown and table below show the details.
How the projection works
Starting from your current balance, the calculator adds contributions monthly and grows the balance at a steady monthly-equivalent return. Each year, contributions increase by the percentage you choose (useful if you save more as your income grows). Finally, the result is divided by cumulative inflation to show its purchasing power today.
The formula
Real value = Final balance ÷ (1 + inflation)years
Keep expectations realistic
Real returns vary year to year, and the order of returns matters, especially near retirement. Use conservative assumptions and revisit them annually.
Worked example
With these inputs: starting amount$25,000; contribution$6,000; everyYear; increase contributions yearly by2%; expected annual return7%; years to invest25; inflation2.5%.
The calculator gives a projected portfolio value of $604,506 ($326,065 in today’s dollars). Other results: total invested$217,182, investment growth$387,324, inflation-adjusted value$326,065, final yearly contribution$9,651.
What your results mean
The projected balance assumes a steady average return every year, but real markets fluctuate. Treat it as a planning estimate, and look at the inflation-adjusted figure for the value in today’s dollars.
Tips
- Try a conservative return (5–6%) as well as an optimistic one.
- Raise contributions with each pay raise; the annual increase field shows the impact.
- Low-cost index funds keep more of your return compounding.
Frequently asked questions
What is a realistic annual return for investments?
The S&P 500 has historically averaged roughly 10% a year before inflation over long periods, but future returns are uncertain and a diversified portfolio with bonds will usually earn less.
How much will $500 a month be worth in 30 years?
About $487,000 at a 6% average annual return and about $704,000 at 8% (returns compounded monthly at the equivalent of the annual rate). You contribute $180,000; the rest is growth.
What return should I assume?
Many planners use 5%–7% for a diversified stock-heavy portfolio before inflation, lower for bonds.
Why show inflation-adjusted value?
$1 million in 25 years will buy much less than today. Real value helps you plan in today’s terms.
Are taxes included?
No. Taxes depend on account type (401(k), IRA, taxable).
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