TL;DR: Reinvesting dividends means each payment buys more shares instead of landing as cash, so your share count, and therefore your next payment, grows on its own schedule. In the worked example below, 100 shares at an illustrative flat $50, with a dividend starting at $2.00 per share and growing 5 percent a year, become 124.14 shares worth $6,207.11 in five years, against $6,105.13 of value plus collected cash without reinvestment. The five-year gap is small. The mechanism is the point: given decades, the reinvested stream compounds in a way the cash stream cannot.
Key Takeaways
- A DRIP buys fractional shares, so the whole dividend goes back to work instead of waiting in cash for a full share's price.
- Reinvestment compounds twice over when the dividend itself grows: more shares, each paying a larger dividend, each payment buying still more shares.
- The worked example keeps the share price deliberately flat to isolate the reinvestment effect. Real prices move, which changes the share count a dividend buys, sometimes helpfully.
- In a taxable account, reinvested dividends are generally taxed in the year paid, as if you had received the cash, even though you never held it. The reinvestment also creates many small tax lots to track.
- Whether reinvestment helps your plan depends on what the cash would otherwise do. Our guide to tracking a dividend portfolio without a spreadsheet covers where the growing lot list belongs.
How does dividend reinvestment work?
When a company you own pays a dividend, the default is cash in your account. A dividend reinvestment plan, offered through most brokers and by some companies directly, intercepts that cash and buys more of the same stock on the payment date, at that day's price. Because plans buy fractional shares, a $218.40 dividend at a $50 share price buys 4.368 shares, not 4 shares with $18.40 left over.
From that point the arithmetic takes over. Your next dividend is calculated on the larger share count. If the company also raises its dividend per share, the two growth sources multiply. A dividend reinvestment calculator exists to run that multiplication forward over your own yield, dividend growth, price, and horizon, because after a few years the chain is tedious to run by hand. The five-year version below is short enough to check line by line, and you should, because trusting the shape of the table is what makes the longer calculator outputs believable.
A five-year worked example, year by year
Every figure here is illustrative, and one simplification is stated plainly: the share price is held flat at $50 for all five years, so the table isolates reinvestment and dividend growth alone. Real prices move, and a falling price makes each dividend buy more shares while a rising price makes it buy fewer.
Starting position: 100 shares at $50, costing $5,000. Dividend: $2.00 per share in year 1, a 4.0 percent yield on the $50 price, growing at 5 percent a year.
| Year | Dividend per share | Dividend received | Shares bought at $50 | Shares at year end | Holding value | | --- | --- | --- | --- | --- | --- | | 1 | $2.00 | $200.00 | 4.0000 | 104.0000 | $5,200.00 | | 2 | $2.10 | $218.40 | 4.3680 | 108.3680 | $5,418.40 | | 3 | $2.205 | $238.95 | 4.7790 | 113.1470 | $5,657.35 | | 4 | $2.3153 | $261.96 | 5.2393 | 118.3863 | $5,919.32 | | 5 | $2.4310 | $287.80 | 5.7560 | 124.1423 | $6,207.11 |
Figures are rounded for display; share counts and values are computed from unrounded values. Check the chain on any row: year 3's dividend is 108.3680 shares times $2.205, which is $238.95, and that buys 4.7790 more shares at $50.
Now the comparison that isolates the reinvestment effect. Take the dividends as cash instead, same shares, same growing dividend: you still hold 100 shares worth $5,000, and the cash collected across five years is $200.00 plus $210.00 plus $220.50 plus $231.53 plus $243.10, which totals $1,105.13. Combined value: $6,105.13. Reinvestment ends at $6,207.11, ahead by $101.98, in a flat market, purely because years 2 to 5 paid dividends on shares that only existed because earlier dividends bought them. Five years shows the mechanism honestly and modestly. The same mechanism, run over twenty or thirty years and a rising dividend, is where reinvestment earns its reputation, and also where a calculator's output starts depending heavily on the assumptions you choose.
What should you watch when you run your own numbers?
- The dividend growth assumption. In the example, growth contributed as much as reinvestment did. A calculator fed an aggressive growth rate will produce an aggressive future. Use the company's actual history as a ceiling for your optimism, not a floor.
- The price path. Flat was a teaching device. A real calculator either holds price constant or grows it at an assumed rate, and the assumed rate changes how many shares each dividend buys. Ask which your calculator does before quoting its output.
- Yield on cost quietly transforms. By year 5, the position's annual dividend has grown to $287.80, paid on every share held at the start of that year, reinvested shares included. Against the original $5,000 cost, that income is a yield on cost of about 5.8 percent, up from 4.0 percent at purchase. This is the snowball income investors describe, visible here in small numbers.
- Fees and plan terms. Broker plans commonly reinvest without commission, but terms vary, and some company-run plans carry fees. A fee on every small purchase eats the fractional-share advantage.
What are the tax and record-keeping realities?
Two, and both are routinely discovered late. First, tax: in a taxable account, a reinvested dividend is generally treated the same as a dividend received in cash for tax purposes in the year it is paid, because you directed the payment rather than never receiving it. In tax-advantaged accounts the treatment differs. This is general information about how reinvestment is commonly treated, not tax advice for your situation; the IRS publishes the governing guidance on dividend income.
Second, records: every reinvestment is a purchase, creating a new tax lot with its own price and date. Five years of quarterly dividends on one holding is twenty lots. A decade across a portfolio is hundreds. When you eventually sell, cost basis depends on those records being right. This is the maintenance load that pushes income investors from spreadsheets toward a tracker, the trade-off examined in our comparison of portfolio trackers and spreadsheets in this series, and the reason to confirm your broker tracks and reports reinvestment lots correctly before the lot count grows teeth.
FAQ
How much faster does a portfolio grow with DRIP? In the flat-price worked example, five years of reinvestment produced $6,207.11 against $6,105.13 for taking the cash, a $101.98 edge that comes entirely from dividends paid on reinvested shares. The edge compounds with time, dividend growth, and any price appreciation on the growing share count, and it shrinks if the cash alternative was itself invested elsewhere at a good return. There is no universal multiple. That compounding arithmetic, run on a whole portfolio rather than one dividend stream, is the subject of our compound growth calculator guide.
Are reinvested dividends taxed? Generally yes in a taxable account, in the year the dividend is paid, as though you had taken the cash. Tax-advantaged accounts follow their own rules. Confirm your treatment against current IRS guidance or a tax professional, because the reinvestment creates a tax record even though no cash passed through your hands.
What dividend growth rate should I assume in the calculator? One grounded in the company's own history and current payout, stated as an assumption. The example uses 5 percent for roundness. Feeding a calculator the highest growth rate a company ever posted, sustained forever, manufactures a future the company never promised.
Can I reinvest dividends from only some holdings? Usually yes. Reinvestment elections are typically set per holding at most brokers, so you can reinvest the dividends of companies you want more of, and take cash from positions you are holding steady or phasing out. The election is a portfolio decision, not just a convenience setting.
Sources
- Investor.gov (U.S. Securities and Exchange Commission), investor education material on dividends and dividend reinvestment, accessed October 2026.
- Internal Revenue Service, guidance on dividend income and its taxation, accessed October 2026.
- The year-by-year table in this post was computed directly from the stated inputs: 100 starting shares, $50 price held flat, $2.00 initial dividend per share growing at 5 percent annually, full reinvestment including fractional shares.
Educational content, not financial advice. The worked example uses a hypothetical holding, a deliberately flat share price, and illustrative dividend figures. It is not a projection of any security's returns and not a recommendation to buy or sell any security.
