Investment Calculator — United States
See what an existing investment plus steady monthly contributions could build — after fees, inflation, and the federal tax bill many calculators ignore.
Published by GrowThenDraw Editorial Team · Editorial policy · Methodology & sources
If you sold everything at the end (one tax year, taxable account): estimated tax $6,491 — you keep $96,785.
| Year | Invested | Value | Gain |
|---|---|---|---|
| 1 | $6,000 | $6,335 | $335 |
| 2 | $12,000 | $13,334 | $1,334 |
| 3 | $18,000 | $21,065 | $3,065 |
| 4 | $24,000 | $29,606 | $5,606 |
| 5 | $30,000 | $39,041 | $9,041 |
| 6 | $36,000 | $49,464 | $13,464 |
| 7 | $42,000 | $60,979 | $18,979 |
| 8 | $48,000 | $73,700 | $25,700 |
| 9 | $54,000 | $87,752 | $33,752 |
| 10 | $60,000 | $103,276 | $43,276 |
You're probably already dollar-cost averaging
If money leaves your paycheck for a 401(k) every two weeks, congratulations — you already dollar-cost average. It's the unglamorous strategy of investing the same amount on a schedule no matter what the market is doing. When prices are high, your $500 buys fewer shares; when the market drops, the same $500 quietly buys more. Over the years, that autopilot discipline — not clever timing — is how most real portfolios get built.
This calculator puts numbers on it. Pick a monthly amount, a timeframe and a return assumption, and watch what compounding does with boring consistency. (Investors from India know the identical strategy as a SIP — same math, different name.)
The assumptions, out in the open
The default 10% return is the S&P 500's long-run average with dividends reinvested — a historical fact, not a promise. Planning at 7–8% is the conservative move, and the field is yours to change. The expense ratio matters more than it looks: a 1% fund fee quietly consumes roughly a quarter of a 30-year portfolio, which is why it gets subtracted from the return before anything compounds.
The inflation toggle restates your final number in today's dollars. A million dollars in 2050 sounds impressive; knowing it spends like $550,000 today is what's actually useful.
The ending nobody calculates: the tax bill
None of these accounts tax your growth while you hold. The reckoning comes when you sell — capital-gains rules for a brokerage account, ordinary income for a traditional 401(k), nothing at all for a qualified Roth IRA. That's why this page also estimates the tax if you sold everything at the end, using the 2026 federal brackets. And when you're ready to plan the income side, the retirement withdrawal calculator applies the same rules to every monthly paycheck you draw.
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Frequently asked questions
Is dollar-cost averaging the same as a SIP?
Yes — SIP (systematic investment plan) is the Indian-English name for the identical strategy, and pound-cost averaging is the British one. A fixed amount at a fixed interval, whatever the market is doing. The math on this page serves all of them; only the tax treatment is US-specific.
What annual return should I assume for the S&P 500?
The long-run nominal total return of the S&P 500, with dividends reinvested, has averaged roughly 10% per year. That is a historical average, not a promise — many planners model 7–8% to be conservative, and you can set any rate you like. Remember to subtract your fund's expense ratio.
Does this calculator include taxes?
Yes, at the moment taxes actually apply: the page estimates the capital-gains bill if you sold the whole portfolio at the end (one tax year, 2026 federal brackets), and the companion systematic-withdrawal calculator taxes every monthly withdrawal — including the 3.8% net investment income tax. During accumulation itself, US accounts don't tax growth you haven't realized.
I'm an NRI living in the US — can I use this?
Yes, this tool is built for exactly that: investing in USD through US accounts under US tax rules. Note that SIPs into Indian mutual funds from the US involve different tax treatment (including PFIC rules) that this calculator does not model.
Tax figures for 2026 last verified 3 July 2026 against the official source — how we calculate.
GrowThenDraw is not a registered investment adviser, broker-dealer, or tax preparer, and is not affiliated with the SEC, FINRA, or the IRS. All results are educational estimates only — consult a licensed financial advisor or CPA before acting.
Relevant bodies in this jurisdiction: SEC / FINRA (investments), IRS (tax).