Stock, Investment & DCA Calculator — What Your Portfolio Actually Did

Using it as a dollar-cost averaging (DCA) calculator

Dollar-cost averaging means investing a fixed amount on a fixed schedule rather than all at once. This calculator does it directly: set Invest by to a recurring contribution, choose the amount per period and the frequency, and it buys at the real closing price on every one of those dates rather than at an assumed average.

That distinction matters more than it sounds. A DCA calculator that applies one flat annual return to your contributions cannot tell you what actually happened, because your result depends entirely on the sequence of prices you bought at. Buying through a fall gives you a lower average cost and a better outcome than the headline return suggests; buying through a steady rise gives you a worse one.

The number to look at is your average cost per share, not the stock’s return over the period. Your gain is the final price divided by what you actually paid on average. That is why a stock that rose 11.8x over a decade returns roughly 3.9x on a weekly plan — you were buying all the way up, so most of your shares cost far more than the first ones did.

Increasing your contribution each year

Use Increase yearly to raise the contribution annually, which is closer to how most people actually invest as their income grows. Even a small annual step-up changes the total substantially over ten or twenty years, because the later contributions are the largest and still get years of compounding.

Reinvesting dividends

Turn on dividend reinvestment (DRIP) to have income buy further shares rather than sit as cash. On a low-yield holding it barely moves the result; on a dividend-paying one it is a large part of the total return, and leaving it out understates what you would have had.

To see this worked through on a real holding, our breakdown of the Apple stock 10 year return compares a $10,000 lump sum against $100 a week over the same decade, with dividends reinvested both ways.

For a plan built on an assumed rate of return rather than real price history, use the compound interest calculator instead — and our guide to how compound interest works explains why the final years of a long plan add so much more than the early ones.

How this portfolio calculator works

This free stock investment calculator projects how a portfolio of real US-listed stocks and ETFs could grow. Pick your stocks and, for each one, set two things: what share of your money goes into it (the split) and how fast you expect it to grow each year (its own growth rate). Because every holding is projected at its own rate, a high-growth pick and a steady dividend payer behave differently — just like a real portfolio. You then add a starting amount, optional regular contributions, a portfolio dividend yield, and an inflation rate, and the tool projects the whole mix forward year by year.

Under the hood the calculator treats each stock as its own growing stream. For every period (monthly, quarterly, and so on) it adds your contribution to that stock's balance, then applies its share of the annual return. Returns compound quarterly by default — you can switch to monthly, semi-annual, or annual under the results to see how compounding frequency changes the outcome. At the end it adds up every stream to show your projected balance, splits it into starting amount, contributions, and market growth, and converts the total into today's dollars so inflation doesn't flatter the number.

What each input means

• Split (%) — how your money is divided between stocks. Splits must add up to 100%. The calculator shares them out equally as you add stocks, and you can override any of them.
• Growth rate (%) — your own yearly assumption for how much that stock appreciates in price. This is the number you control; the calculator never predicts it for you.
• Starting amount — a one-off lump sum you begin with. Enter 0 if you're starting from scratch.
• Contribution + frequency — how much you add on a schedule (say $500 a month). Investing a fixed amount regularly is called dollar-cost averaging.
• Dividend % / yr — the portfolio's average dividend yield. Choose whether dividends are reinvested (they buy more shares and compound) or paid out as cash.
• Inflation % / yr — used only to show the "today's dollars" figure, so you can see what your future balance is really worth.
• Compounding — how often growth is applied. More frequent compounding produces a slightly higher result for the same annual rate.

Worked example

Suppose you start with $10,000, add $500 a month for 20 years, and split your money 60/40 between two stocks — one you expect to grow 12% a year and one you expect to grow 7% a year — with a 1.5% dividend yield reinvested and compounding quarterly.

• You will have personally put in $10,000 + ($500 × 12 × 20) = $130,000 over the two decades.
• The 60% stream (12% plus reinvested dividends) grows fastest and does most of the heavy lifting.
• The 40% stream (7%) grows more slowly but steadies the ride.
• The projected balance lands well above your $130,000 of contributions — and that gap is your market growth, the money your money earned.

Change any single input — a higher monthly contribution, one more year, a slightly lower growth assumption — and watch how much the final figure moves. That sensitivity is the real lesson: how much you contribute and how long you stay invested usually matter more than picking the "perfect" stock.

Choosing a realistic growth rate

The growth rate is the most important number you enter, so it's worth grounding it in history rather than hope. Over multi-decade periods the broad US stock market (the S&P 500) has historically averaged roughly 10% a year over the long run (the S&P panel in the tool shows SPY since 1993, a shorter and more favourable window) before inflation, or about 6–7% after inflation — but with large swings, losing years, and no guarantee it repeats. Individual stocks can do far better or far worse than the market and are much less predictable.

Type of holding	Rough historical range*
Broad market index (e.g. S&P 500)	~7–10% / yr
Large, established "blue-chip" stock	~5–10% / yr
Fast-growing individual stock	Highly variable
Dividend-focused stock	~4–8% / yr + dividends

*Long-run averages before inflation, shown only to help you pick a sensible assumption. Past performance does not predict future returns.

A good habit is to run the calculator two or three times — an optimistic rate, a middle rate, and a conservative one — so you see a range of outcomes rather than a single false-precision number.

Holding these shares in Canada? Every figure on this page is in US dollars. Your real return also includes the CAD/USD move over the same period, and it is not a rounding error — from January 2002 to July 2011 the S&P 500 returned +1.4% a year in US dollars but −3.9% a year in Canadian dollars. From July 2011 to January 2016 it reversed, turning +9.4% into +19.5%. A Canadian-dollar view of this tool is being built.

Using it as a dividend calculator

Every stock and ETF in the list carries its current dividend yield, so the tool doubles as a dividend calculator: build a portfolio and the Dividend income figure shows the annual income that mix would throw off at today’s yields, before tax. Change the weights and it updates, which makes it straightforward to see what shifting from a growth-heavy mix toward dividend payers actually does to your income.

Two things worth understanding about that number. It uses the current yield, not the yield you would have locked in by buying years ago — someone who bought a stock a decade ago and has watched the dividend grow is earning far more on their original cost than the headline yield suggests. And it assumes the dividend holds. Dividends are a decision made by a company’s board every quarter, not a contract, and they get cut in bad years.

Not modelled: dividend growth over time, and tax. Both matter, and where you hold the shares changes the tax materially — a Canadian holding US dividend payers faces US withholding tax that an RRSP is exempt from under the Canada-US tax treaty but a TFSA is not. The DRIP toggle above shows the difference reinvesting makes to the total, which over long periods is usually larger than people expect.

Where you hold this portfolio changes what you keep

The projection above applies no tax at all — it simply grows one pot of money at the rates you enter. How close that is to your real outcome depends on the account your shares sit in.

• Taxable brokerage account. Ordinary dividends are included in your ordinary income for the year you receive them (IRS Topic 404), and a capital gain is taxed when you sell (IRS Topic 409). That makes the reinvested-dividend (DRIP) result here slightly optimistic: in reality a slice of every dividend goes to tax before it can buy more shares. Entering a lower dividend yield is a rough way to allow for the drag.
• Traditional 401(k) or IRA. Salary deferrals are excluded from your taxable income and nothing is skimmed off along the way, so the growth curve here is the closest match to reality — but distributions, including earnings, are taxable when you take them in retirement (IRS — 401(k) plans). Read the ending balance as pre-tax money.
• Roth IRA. You contribute after-tax dollars and qualified distributions come out tax-free (IRS — Roth IRAs), so the figure on screen is the cleanest match to what you would actually keep.

Account type changes the tax, not the risk. The correlation map, risk contribution and crash drawdowns above are identical wherever the shares are held. This is general information, not tax advice.

Background from US regulators: the SEC’s Beginners’ Guide to Asset Allocation, Diversification, and Rebalancing and FINRA’s guide to investment risk.

Common mistakes to avoid

• Using a growth rate that's too high. Assuming 20%+ a year for decades produces exciting but unrealistic numbers. Anchor to history.
• Ignoring inflation. A million dollars in 30 years is worth far less than a million today — always check the "today's dollars" figure.
• Forgetting that returns aren't smooth. Real markets fall as well as rise; a steady projected line hides some very bumpy years.
• Treating the output as a promise. This is a planning tool, not a prediction. Use it to compare choices, not to guarantee a result.

Frequently asked questions

Does this calculator predict stock prices?

No. It never guesses what a stock will do. It grows your money at the rate you enter, so the projection reflects your own assumptions — not a forecast from us.

What growth rate should I use?

A sensible starting point is the long-run market average of around 7–10% a year before inflation, adjusted up or down for how aggressive or conservative each holding is. Running a few different rates gives you a realistic range.

Should I reinvest dividends?

Reinvesting (DRIP) uses dividend cash to buy more shares, which then earn returns of their own — a meaningful compounding boost over long periods. Toggle it off to see dividends paid out as cash instead.

What's the difference between nominal and "today's dollars"?

Nominal is the raw future balance. "Today's dollars" divides that by inflation over the same period, showing what the money would actually buy at today's prices. It's usually the more meaningful figure for planning.

Why give each stock its own growth rate?

Because real portfolios aren't uniform. A high-growth stock and a steady dividend payer are expected to behave very differently, and projecting each at its own rate is far more realistic than applying one blended number to everything.

How does compounding frequency change the result?

For the same annual rate, compounding more often (monthly vs. annually) produces a slightly higher final value, because returns start earning returns sooner. The default here is quarterly; you can change it under the results.

What is volatility, and how does the risk rating work?

Volatility measures how bumpy a stock's ride has been — how far it swings up and down. We turn each stock's real historical volatility into a simple 1–7 risk rating so you can compare holdings at a glance: 1 is calm, 7 is very jumpy.

What does "dollar-cost averaging" mean?

Investing a fixed amount on a schedule (say $200 a month). You automatically buy more shares when prices are low and fewer when they're high, so you don't have to time the market. Choose "Recurring" above to model it.

Why is my mix less risky than the riskiest stock in it?

Because stocks that don't move together partly cancel each other out. Mixing them lowers your overall volatility below the simple average of the parts — that gap is the "diversification benefit," and the tool shows it for your exact mix.

Is this financial advice?

No. It's an educational projection tool. It doesn't recommend any stock or strategy and can't account for your personal situation, taxes, or fees. For decisions about your money, speak to a licensed financial professional.

Are the stock prices live?

Stock prices shown in the picker are updated once daily after the US market close, so they reflect recent closing values rather than live intraday trading.

Estimate only

This is a projection based on the growth rates you enter — real stock returns vary, include losing years, and are never guaranteed. Figures are for illustration only and are not investment, tax, or financial advice. See our disclaimer.