A dividend reinvestment plan, or DRIP, takes each dividend a fund or stock pays you and immediately uses it to buy more shares. That one habit changes the shape of long-term growth: instead of income arriving as a flat stream of cash, it becomes a stream of new shares, and each new share pays its own dividends next time. This guide walks through exactly how that compounding works, using the same month-by-month engine that powers our SCHD dividend calculator and dividend snowball calculator.
Every number below was produced by running that code with clearly labeled example inputs. They are round numbers picked to make the math easy to follow. They are not predictions for any fund, and real dividends and prices move around far more than a constant-rate model can show.
What DRIP actually does
Without reinvestment, a dividend investment has two moving parts: the share price and the dividend per share. Your share count stays the same unless you buy more with new money. With DRIP turned on, a third part starts moving: your share count grows on its own. Each payout is divided by the current share price, and the result is added to your holdings as whole or fractional shares.
That is the whole mechanism. There is no special return source hiding inside a DRIP. The dividend you reinvest is money you would otherwise have received as cash. What DRIP changes is what that money does next: it is put to work buying more income-producing shares right away, rather than sitting in a cash balance.
The formulas
Our calculators simulate one month at a time. In plain notation, for each month m:
DPS_year = price_0 × yield × (1 + g_div)^(year − 1)
payout = shares × DPS_year ÷ payouts_per_year
shares_new = shares + payout ÷ price_m
Here g_price is the yearly share-price growth rate, g_div is the yearly dividend growth rate, and yield is the starting dividend yield. A quarterly payer pays in months 3, 6, 9 and 12, so payouts_per_year is 4. A monthly payer uses 12. The dividend per share steps up once per year, and the price grows smoothly each month.
If you add a monthly contribution, it buys shares at the start of the month at that month’s price. Reinvested dividends buy shares at the price in the payout month.
Worked example 1: one year by hand
Start with the simplest case so you can check every step on a calculator. Example inputs: $10,000 invested at a share price of $50 (200 shares), a 4% yield, quarterly payouts, and, to isolate the effect of DRIP, no price growth and no dividend growth. A 4% yield on a $50 share is $2.00 per share per year, or $0.50 per quarter.
| Quarter | Dividend paid | Shares bought at $50 | Shares after DRIP |
|---|---|---|---|
| Q1 | $100.00 | 2.0000 | 202.0000 |
| Q2 | $101.00 | 2.0200 | 204.0200 |
| Q3 | $102.01 | 2.0402 | 206.0602 |
| Q4 | $103.03 | 2.0606 | 208.1208 |
The first payout is exactly 200 × $0.50 = $100, which buys two shares. The second payout is slightly bigger, because it is paid on 202 shares instead of 200. By the end of the year you hold 208.12 shares and collected $406.04 in dividends, compared with exactly $400.00 without DRIP. The extra $6.04 is small, but it is pure compounding: dividends earned on dividends.
Mathematically, with a flat price and flat dividend, DRIP turns a 4% yield paid quarterly into growth of 1% per quarter. Over a year, that is (1.01)^4 − 1 ≈ 4.06%, which is the same idea as the gap between an APR and an APY.
Worked example 2: 20 years with no growth at all
Now run the same $10,000 for 20 years, still with zero price growth and zero dividend growth. The only thing that can make the DRIP account grow is reinvestment.
| After 20 years | DRIP on | DRIP off (take cash) |
|---|---|---|
| Shares owned | 443.34 | 200 |
| Dividends in year 20 | $865 | $400 |
| Total dividends over 20 years | $12,167 | $8,000 |
| Ending value (shares + cash) | $22,167 | $18,000 |
Without reinvestment, the cash route gives you 20 years × $400 = $8,000 of dividends plus your original $10,000, for $18,000. With DRIP, the share count more than doubles, and the ending value is $22,167, which matches 10,000 × 1.01^80. The year-20 dividend in the DRIP account is more than twice the original $400, even though the dividend per share never rose. All of that growth came from owning more shares.
Worked example 3: adding dividend growth and price growth
Real dividend funds don’t sit still, so the next run adds two assumptions. Example inputs: 5% annual dividend growth and 5% annual price growth, with the same $10,000 start, $50 price, 4% starting yield, 20 years and no new contributions.
| Example inputs, no contributions | DRIP on | DRIP off |
|---|---|---|
| Shares after 10 years | 294.26 | 200 |
| Shares after 20 years | 432.95 | 200 |
| Dividends in year 1 | $406 | $400 |
| Dividends in year 10 | $891 | $621 |
| Dividends in year 20 | $2,136 | $1,011 |
| Yield on cost in year 20 | 21.36% | 10.11% |
| Ending value | $57,437 | $39,759 |
Two forces now stack. In the cash column, the income grows only because the dividend per share grows by 5% a year, so year-20 income is roughly $400 × 1.05^19. In the DRIP column the income grows for that reason and because the share count keeps rising. That is why the year-20 dividend in the DRIP column is about double the cash column.
Notice something less obvious, too. Share-count growth slows down when prices rise. Each reinvested dollar buys fewer shares at $80 than at $50. In this example the yield on the current price stays at 4% the whole time (both price and dividend grow at 5%), so DRIP keeps adding about 4% more shares per year. If the price grew faster than the dividend, the current yield would shrink and DRIP would add shares more slowly.
Yield on cost: the number that makes DRIP look magical
Yield on cost divides this year’s dividends by the total money you put in. In the example above, the DRIP account’s year-20 yield on cost is 21.36%, even though the yield on the current price was 4% all along. The number is real, but read it carefully. It measures income relative to your original dollars, which have also lost purchasing power over 20 years. It is a useful way to track an income stream, not a return you could earn by buying today.
Worked example 4: with monthly contributions
Most people keep investing. Add $500 a month to the previous example inputs, so the total contributed over 20 years is $130,000.
| With $500/month (example inputs) | DRIP on | DRIP off |
|---|---|---|
| Total contributed | $130,000 | $130,000 |
| Dividends in year 20 | $14,195 | $8,654 |
| Total dividends over 20 years | $113,271 | $80,307 |
| Ending value | $383,932 | $309,743 |
The DRIP-off ending value includes all the dividends collected as cash, so the gap between the columns isn’t the dividends themselves. It is the growth those dividends would have earned if they had been reinvested as shares that rose in price and paid more dividends.
The crossover point
The dividend snowball calculator tracks one more milestone: the first year your annual dividends exceed what you contribute in a year. Using the same example inputs ($10,000 start, $500/month, 4% yield, 5% dividend growth, 5% price growth, DRIP on) over 30 years, annual dividends pass the $6,000 of yearly contributions in year 13. By year 30 the model shows $37,714 of annual dividends ($3,143 a month) on $190,000 contributed. After the crossover, the portfolio adds more new shares through its own income than through your paycheck.
How the yield changes the compounding speed
With no price or dividend growth, the only source of growth in the share count is reinvested dividends, so the yield sets the pace. Same $10,000 example, 20 years, flat price and flat dividend per share:
| Yield (example) | Value after 20 years, DRIP on | Value after 20 years incl. cash dividends, DRIP off | Cash dividends collected, DRIP off |
|---|---|---|---|
| 2% | $14,903 | $14,000 | $4,000 |
| 4% | $22,167 | $18,000 | $8,000 |
| 6% | $32,907 | $22,000 | $12,000 |
Higher yields compound the share count faster in this stripped-down case. Note how the gap between the two columns widens with the yield: at 2% the DRIP advantage after 20 years is $903, while at 6% it is $10,907. With DRIP off, the dividend cash adds up in a straight line, because the share count never changes. With DRIP on, each payment buys shares that pay their own dividends, so the line curves upward. Over longer periods, and once price growth and dividend growth are added back in, that curve gets steeper, which is why the 30-year tables earlier in this guide show much larger gaps than this 20-year flat example. That does not mean higher-yield investments are better: in real markets, high-yield funds often have slower price and dividend growth, and total return is what matters. Our guides on dividend growth vs high yield and high-dividend vs dividend growth ETFs look at that trade-off with growth included.
DRIP in practice
Most brokerages offer automatic dividend reinvestment as an account setting, often selectable for each holding. Many now reinvest into fractional shares, so the entire dividend is invested rather than leaving a small cash remainder. Some companies also run their own direct reinvestment plans through a transfer agent, which may have different rules and fees. Whichever route you use, reinvested shares typically count as new purchases for tax purposes, each with its own cost basis, so keep your broker statements. That matters when you eventually sell in a taxable account, because the gain on each lot is measured from its own purchase price. Reviewing the reinvestment setting once a year, for example when you rebalance, helps make sure each holding is still doing what you intended.
Payment frequency affects when the reinvestment happens, but its effect on long-run growth is small compared with yield, growth and time. Our guide on monthly vs quarterly dividends quantifies that difference. A more useful number to watch is your yield on cost, which rises as DRIP adds shares and dividends grow, and the dividend crossover point, which marks when your dividends start contributing more each year than you do.
What DRIP doesn’t change
- Taxes. In a taxable U.S. brokerage account, reinvested dividends are generally still taxable in the year they are paid, even though you never received cash. Our calculators do not deduct taxes. In tax-advantaged accounts the treatment is different. Check IRS guidance or a tax professional for your situation.
- Total return. A dividend is paid out of the fund’s value. On the ex-dividend date the price typically drops by about the dividend amount. DRIP doesn’t create extra value. It keeps the money invested instead of letting it sit in cash.
- Risk. A constant-rate model can’t show dividend cuts, price crashes or sequence risk. The example rates here are inputs, not expectations.
- Fees. Fund expense ratios and any trading costs are not modeled.
DRIP vs taking the cash: how to decide
The math favors reinvesting whenever you would otherwise leave the cash idle. If you would spend the dividends on living costs, as many retirees do, taking cash is the point of an income portfolio, and the DRIP-off column is the honest model. A middle path many investors use is to turn DRIP off and send the cash to whatever is underweight in the portfolio. That keeps the money invested while helping you rebalance.
You can also think about it in terms of the Rule of 72. In worked example 2, DRIP alone produced 4.06% a year of compound growth. 72 ÷ 4.06 ≈ 17.7 years to double the share count, and the table confirms the shares roughly doubled by year 20.
Try it with your own numbers
Every table above can be reproduced. Open the SCHD calculator (quarterly payouts) or a monthly payer like the JEPI calculator, type in the example inputs, and toggle DRIP on and off. Then replace the inputs with your own assumptions. Try a pessimistic case, such as zero dividend growth, next to an optimistic one. The range between them is more useful than any single projection.
