What is DCA?
Dollar-cost averaging: investing the same amount at fixed intervals without trying to pick the moment. It is what an automatic monthly savings plan does.
Historical DCA
DCA calculator: what you would have investing every month in the S&P 500 or MSCI World
Pick an ETF, a monthly amount and a period. The calculator buys at each month's close with the ETF's real euro prices, dividends included, and shows what you put in, what it would be worth and the worst moment you would have lived through.
Final value€46,685Investing €200 a month in IWDA from Jan 2017 to Sep 2026, you would have put in €23,400 and would have €46,685.
Contributed€23,400
Gain€23,285
Annual return (IRR)13.8%
Average purchase price€64.73
Worst moment: in Mar 2020 your portfolio was down €168 (-2.2%) on what you had put in so far.
Formula
361.48 × €129.15 = €46,685
Price in Sep 2026: €129.15
If you had invested the €23,400 at once in Jan 2017
Final value€72,325
Annual return12.4%
IWDA (MSCI World) · Prices: Yahoo Finance, last close of each month adjusted for dividends, in euros, up to Sep 2026.
How it is calculated
Every month in the period the contribution buys at that month's closing price; the initial amount, if any, buys in the first month. The purchase fee comes out of each contribution. The final value is the units accumulated times the last month's price. The annual return is the IRR: it accounts for each euro being invested for a different length of time, so it is the figure you can compare with a savings account.
Why you buy more when prices fall
With the same amount every month, you buy more units when the price falls and fewer when it rises. That is why your average purchase price ends up below the average price over the period. It does not guarantee a gain: if the market falls and does not recover within your horizon, you lose too.
DCA versus investing everything at once
The calculator compares your plan with investing the same total in the first month. In a market that rises over the long run, being fully invested earlier usually wins, because the money works for longer; DCA wins when the period starts just before a fall. For most people the real question is different: investing their salary as it arrives, and that is already DCA.
What to keep in mind
These are Yahoo Finance prices adjusted for dividends, in euros: the ETF already deducts its ongoing charges, but there is no custody fee, tax or spread. Each series starts when the data is reliable, not when the ETF launched. Past performance does not guarantee future results.
Frequently asked questions
Is DCA better than investing a lump sum?
With the money already available, investing at once has won more often, because the market rises in more months than it falls. DCA lowers the risk of buying just before a fall and is easier to stick with. You can compare both in the calculator by changing the period.
Which ETF does it use for the S&P 500 and the MSCI World?
SXR8 (iShares Core S&P 500) for the S&P 500, IWDA (iShares Core MSCI World) for the MSCI World, VWRL (Vanguard FTSE All-World), EQQQ (Invesco Nasdaq-100) and EMIM (iShares Core MSCI EM IMI), all on their euro listing.
Why does the annual return differ from the index?
Because each contribution was invested for a different length of time: the latest ones have barely had time to grow. The IRR weights each euro by how long it was invested. The lump-sum block shows the ETF's own annual return over the period.
Calculators
- Compound interest calculatorHow an initial amount and monthly contributions grow year by year at a constant return.
- Index fund vs ETF tax (Spain)How much the tax-free fund transfer is worth against an ETF, depending on how often you sell.
- Investment fee calculatorWhat TER, custody and purchase fees cost over the long run, compared side by side for up to five products.
- Foreign dividend withholdingWhat you keep from a foreign dividend as a Spanish resident, and how much excess withholding you could reclaim.
- FIRE and withdrawal calculatorHow much capital covers your spending with the 4% rule, and how many years it lasts with inflation-linked withdrawals.
- Inflation calculatorHow much purchasing power cash loses over time, compared with money invested at a given return.
- Historical inflation calculatorWhat an amount from 1960 to today is worth now, with euro-area, Spanish, German or Dutch inflation.
- Investor risk profile questionnaireSeven questions on horizon, loss tolerance and experience, with an illustrative ETF allocation.