What your investment result shows
The split between your money and growth is the honest shape of investing. For the first stretch, almost everything in the account is money you put there; the growth line only overtakes your deposits well into the projection, and the calculator names the year it happens. After that point the account earns more each year than you add — which is the whole reason to start early rather than to save harder later.
Two lines exist because the other calculators on this search omit them. Fees cost you converts an annual percentage into the dollars removed from your final balance, and the figure is usually shocking: a one-point difference in costs typically removes a fifth or more of a lifetime result, because the fee compounds against you exactly as returns compound for you. Worth in today’s money discounts the balance by inflation, because a projection thirty years out is denominated in dollars that buy noticeably less.
How to use this investment calculator
- Starting amount and contribution — what is invested now, and what you add. Match the frequency to your payday.
- Expected return, before fees. Enter the market return you assume; the fee field handles costs separately, so do not net them yourself.
- Annual fees — your all-in cost. Add the expense ratios of what you hold plus any platform or adviser charge. If you do not know it, that is itself worth finding out.
- Inflation to see real purchasing power, and in the advanced panel a tax rate if the money sits in a taxable account rather than an IRA or 401(k).
Run the whole thing twice — once optimistically, once pessimistically — and treat the gap between the two as the real answer. A single projection presented to two decimal places implies a precision that does not exist.
What fees actually cost
Investment costs are quoted as small annual percentages, which is precisely why they are underestimated. The fee is not charged on your gains; it is charged on your entire balance, every year, including on money that would otherwise have compounded. Over decades that turns a fraction of a percent into a large share of the outcome.
The practical implication is narrow and unusually clear-cut. Between two funds tracking the same index, the cheaper one wins by close to the difference in cost, because their gross returns are near-identical by construction. Between an actively managed fund at 1% and an index fund at 0.05%, the manager must beat the market by almost a point every year merely to draw level. Some do; identifying them in advance is the hard part.
Fees are also the one variable on this page you fully control. You cannot set your return, your tax bracket or the inflation rate — you can choose what you hold and where you hold it.
Why the return you assume is a guess
Long-run US stock market returns have averaged in the region of 7% a year after inflation over very long periods, and that figure gets used as though it were a property of the future. It is a historical average of an extremely volatile series: individual decades have delivered far more and far less, and no rule guarantees the next one resembles the last.
The projection above assumes a steady return, which no market delivers. Real returns arrive as a sequence, and the order matters enormously near the end of the horizon — a poor first decade while the balance is small costs far less than a poor final decade when it is large. That asymmetry is why risk is usually reduced as a goal approaches, and it is the main thing a smooth compounding line cannot show you.
The defensible use of a calculator like this is comparative rather than predictive: what does an extra $100 a month do, what does a lower fee do, what does starting five years earlier do. Those answers are robust even when the absolute number is not.
Where the account lives changes the result
In a taxable brokerage account, dividends and realised gains are taxed as they occur, so each tax bill is money that stops compounding. Set a tax rate in the advanced panel and the result shows the gap against a sheltered account holding exactly the same investments.
That gap is the argument for filling tax-advantaged space first — a 401(k) up to the employer match, then a Roth IRA, then back to the 401(k) — before investing anywhere else. A taxable account still has a role for money you may need before retirement, and it comes with one advantage: realised losses can offset gains, and long-term gains are taxed at preferential rates rather than as income.
What raising the contribution actually does
Of the four things you can change on this page — how much you start with, how much you add, how long you leave it and what it costs you — the contribution and the horizon do almost all the work, and the starting amount matters least. Doubling a monthly contribution roughly doubles the portion of the final balance that comes from deposits, and more than doubles the growth attached to them, because each dollar arrives earlier relative to the end date.
Time is the more powerful of the two and the one you cannot buy back. Ten years of contributions starting now will usually beat fifteen years starting a decade later, even though the latter puts in more money, because the early dollars compound for longer. That is the whole case for starting with an amount that feels too small to matter.
The practical version is to automate the contribution on payday and raise it whenever your pay rises, so the increase never passes through your spending. The paycheck calculator shows what a pre-tax increase costs in take-home, which is usually less than people expect.
What this calculator assumes
- A constant return, compounded regularly. Markets are neither constant nor smooth, and the projection is a shape rather than a forecast.
- Fees charged as a flat annual percentage of the balance, which is how expense ratios work. Flat-dollar platform charges hurt small balances more than this implies.
- Contributions never missed, and never increased. Raising them with your salary would finish materially higher.
- Tax, if set, applied to growth each year — a reasonable model for a dividend-paying taxable account, and pessimistic for a buy-and-hold position where gains are deferred until sale.
- No sequence risk. The order of returns is ignored, which is the single largest simplification here.
These are planning estimates, not advice, and not a projection of any specific investment.
Investing questions people ask
What return should I use?
Something you can defend rather than something that flatters the answer. Many planners use 6–7% a year for a stock-heavy portfolio before inflation, less for a mixed one. The more useful exercise is to run a pessimistic figure and check the plan still works.
Do small fees really matter that much?
Yes, and the fee field above will show you by how much on your own numbers. The reason is that a percentage fee is charged on the whole balance every year, so it compounds against you. Over a working life the difference between 0.1% and 1% is commonly a large fraction of the final result.
Is investing better than paying off debt?
Compare the certain cost of the debt against the uncertain return on the investment. Clearing a balance at 20% beats any realistic expected return; a mortgage at 3% usually does not. Between the two extremes it is a judgement call, and capturing an employer match comes before either.
How is this different from a compound interest calculator?
The maths is the same. The difference is what is being modelled: interest is contractual and known, while an investment return is an assumption about a volatile series. That is why this page prices fees and inflation and talks about the order of returns.