Short answer: yes. $100 a month is enough to dollar cost average, and over long periods it has added up to far more than most people expect. Put into the S&P 500 (via SPY) on the first trading day of every month for the last 20 years, $100 a month, $24,000 in total, was worth about $111,800 at the end of October 2026.
What decides the result is mostly time and what you buy, not the size of each payment. The one thing a small amount does change is how much fees matter.
What $100 a month grew to
Each plan below buys $100 on the first trading day of every month and is valued at the last close of October 2026. The figures come from the same daily price data as our DCA calculators. Stock ETF prices are dividend-adjusted, so they assume dividends were reinvested.
S&P 500 (SPY)
- 5 years (from November 2021): $6,000 in, worth $9,224
- 10 years (from November 2016): $12,000 in, worth $26,756
- 15 years (from November 2011): $18,000 in, worth $59,258
- 20 years (from November 2006): $24,000 in, worth $111,780
- 25 years (from November 2001): $30,000 in, worth $174,192
- 30 years (from November 1996): $36,000 in, worth $239,921
Nasdaq 100 (QQQ)
- 10 years: $12,000 in, worth $33,236
- 20 years: $24,000 in, worth $197,018
Bitcoin and Ether
- Bitcoin, 5 years: $6,000 in, worth $10,782
- Bitcoin, 10 years: $12,000 in, worth $120,101
- Ether, 5 years: $6,000 in, worth $6,079, roughly break-even
Gold
- 10 years: $12,000 in, worth $26,005
- 20 years: $24,000 in, worth $68,223
What the numbers say
Time does most of the work. In SPY, the 10-year plan turned the money put in into about 2.2 times as much, while the 30-year plan multiplied it by about 6.7. The 30-year plan had three times the contributions of the 10-year plan but ended with about nine times the value, because in the later years the balance itself does most of the growing.
The asset matters as much as the amount. The same $100 a month for five years ended with about 1.8 times the money in Bitcoin and about 1.0 times in Ether. A small, steady plan doesn't protect you from a weak asset. Our guide on how to dollar cost average covers choosing what to buy.
These are past results, picked at one end date. A plan valued at the bottom of a bear market looks far worse than the same plan a year later. Over the 5-year windows in particular, the end date can swing the outcome a lot.
When $100 a month is too little
The amount is enough; the costs around it are what can fail a small plan.
- Fixed fees. A $1 fee on every $100 buy takes 1% before the market has done anything. On a $25 weekly buy, the same $1 takes 4%. Our breakdown of the real cost of DCA shows how fixed fees, percentage fees and spreads add up across daily, weekly and monthly schedules.
- Minimum order sizes. Some brokers don't offer fractional shares, so $100 may not buy a whole share of a high-priced ETF. Use a platform with fractional buys, or buy less often in larger amounts.
- Your goal. If you need a specific sum by a specific date, $100 may simply not get there. The savings goal calculator works backwards from a target to the monthly amount it needs.
Make $100 a month work harder
- Automate it so the buy happens whether or not you remember, and especially when markets are falling. (Pausing in a crash has been expensive; see what stopping DCA in a bear market cost.)
- Raise it when your income rises. Moving from $100 to $150 a month after a raise is painless at the time and adds up over decades.
- Keep fees close to zero with a percentage-fee or zero-commission platform.
- Run your own numbers in the S&P 500 DCA calculator, the Bitcoin DCA calculator or the compound interest calculator before you start.
FAQ
Is $100 a month enough to start investing? Yes. In our backtest, $100 a month in SPY for 20 years ($24,000 in total) was worth about $111,800 at the end of October 2026. Time in the market mattered more than the size of each payment.
How much will $100 a month be worth in 10 years? Nobody knows the future. Historically, $100 a month in SPY for the 10 years to October 2026 ($12,000 in) grew to about $26,800, and in gold to about $26,000. Other periods and assets give very different results.
How much will $100 a month be worth in 30 years? In SPY, the 30 years to October 2026 turned $36,000 of contributions into about $239,900, with dividends reinvested and before fees and taxes.
Is it better to invest $100 a month or $1,200 once a year? If you already have the $1,200, investing it at once has historically won more often than spreading it out. If the money arrives monthly from your income, investing it monthly is simply investing as soon as you can. See DCA vs lump sum.
Should I DCA $100 a month into Bitcoin? It has worked over long windows, with large swings: $100 a month for 10 years grew to about $120,100, while the 5-year plan in Ether only broke even. Keep crypto to an amount you can hold through an 80% drop.
