Every start month of this asset's own history, both plans.
Ready-made answers for the assets people ask about most — each one computed from that asset's own month-end prices.
Four steps, about twenty seconds.
Pick the asset
Search any stock or ETF by name or symbol, or use one of the chips. Its whole price history is loaded, not a window.
Enter the amount
The lump sum, and the total the spreading plan pays in. It is in the asset's own trading currency, so there is no hidden exchange rate.
Choose the spread length
Three to thirty-six months. The first monthly slice goes in on the same day the lump sum would have, and the cash still waiting earns nothing.
Read the bars, then pin one
Each bar is one start month. Bars above the line are months the lump sum finished ahead, bars below are months spreading did. Select a bar to see both paths month by month.
The arithmetic is easy. Knowing what it does and does not settle is the hard part.
The win rate is not the whole story. Look at the worst window too — that is the outcome you would have had to live through, and it is the reason people spread anyway.
Change the spread length on the same asset. A longer spread usually lowers the lump sum's win rate in a rising market, because the cash sits out for longer; the chips make 3 against 36 a two-click test.
Spreading is a regret strategy, not a return strategy. Vanguard's 2012 study "Dollar-cost averaging just means taking risk later" found lump sum ahead in about two thirds of 12-month cases across the US, UK and Australia — and still concluded that spreading is reasonable if a bad first year would make you sell.
This test assumes waiting cash earns nothing. A cash account paying interest closes part of the gap — roughly its yield over the months the money is still on the sidelines — so read the median gap as an upper bound, not a fee.
The result stops moving once the last slice is in. From that month on both plans hold the same asset, so the percentage gap is fixed for good; only the money it is worth keeps changing.
Want a single date instead of every date? The what-if investment calculator prices one start.
Deeper guides on our blog that build on the topics in this tool.
The same test on each asset's whole price history: a lump sum against an equal-slice spread over the same number of months, from every start month the data allows.
| Asset | Since | Start months | Lump sum won | Median gap |
|---|---|---|---|---|
| S&P 500 | 1993 | 393 | 79% | +5.9% |
| Nasdaq 100 | 1999 | 320 | 75% | +7.6% |
| Total world (VT) | 2008 | 209 | 72% | +5.2% |
| Total US market (VTI) | 2001 | 293 | 78% | +5.6% |
| Bitcoin | 2014 | 134 | 68% | +23.4% |
| Gold (GLD) | 2004 | 252 | 70% | +5.0% |
| Tesla | 2010 | 185 | 65% | +7.7% |
| Nvidia | 1999 | 322 | 71% | +16.1% |
| Apple | 1980 | 539 | 67% | +9.3% |
| SCHD | 2011 | 169 | 81% | +5.6% |
| VWCE | 2019 | 76 | 74% | +5.6% |
| MSCI World (IWDA) | 2009 | 194 | 80% | +6.0% |
Computed from month-end total-return closes. Data as of 2026-09-10.
| Term | What it means here |
|---|---|
| Lump sum | The whole amount invested on one day — the first month of the window. |
| Dollar-cost averaging (DCA) | The same total split into equal monthly slices. The first slice goes in on the same day as the lump sum; the rest wait, earning nothing. |
| Start month | One month-end in the asset's history. Every month that has enough history after it becomes its own test, which is why a long series produces hundreds of results rather than one. |
| Win rate | The share of start months where the lump sum was worth more at the end of the spread period. |
| Median gap | The middle result once every window is sorted. Half the windows were better than this for the lump sum and half were worse — a fairer summary than the average, which a single 2009 window can distort. |
| Total return | Price movement plus dividends reinvested in the month they were paid. Where an asset pays no dividends the two are the same number, and the caption under the result says which one you are looking at. |
Historically, all at once — most of the time. Markets rise more months than they fall, so money that is already invested has more time to compound than money waiting on the sidelines. Run any broad index above and you will usually see a win rate well above half. The exception is a window that starts just before a crash, and the tool shows you exactly which months those were.
It depends on the asset and the spread length, which is why this page computes it. Three studies put the lump sum ahead: Of Dollars And Data, 80.6% of starting months since 1997 against a 24-month spread; Vanguard 2012, about two thirds of 12-month cases; Morgan Stanley, more than 56% across over 1,000 overlapping 7-year periods. The table below carries our own figures for twelve popular assets.
Vanguard's 2012 paper "Dollar-cost averaging just means taking risk later" tested rolling 12-month periods in the US, UK and Australia going back to 1926 and found a lump sum ended ahead roughly two thirds of the time, by an average of a few percent. Its conclusion was not "never spread": it said spreading buys a smaller worst case, and that is worth paying for if a bad first year would make you sell.
The same arithmetic applies, with one addition: money contributed in January has eleven more months of tax-free growth than money contributed in December, so the account wrapper pushes slightly further toward investing early. Set the spread to 12 months on a broad index above to see the size of the historical gap for the fund you would actually buy.
Yes — that is exactly what the bars below the line are. Every window that starts within a few months of a peak favours spreading, because the later slices buy at lower prices. The catch is that you only know a window was one of those afterwards; select the "worst for lump sum" chip to see one drawn month by month.
The same test answers it: pick the fund you hold in the ISA (a global tracker such as VWCE.DE or IWDA.AS is the usual choice) and set the spread to however many months you were thinking of drip-feeding over. The ISA wrapper changes the tax, not the market history, so the win rate on this page is the one that applies.
Substantially. A three-month spread keeps almost all of the money invested almost immediately, so it behaves like a lump sum; a thirty-six-month spread leaves most of the money in cash for years, and in a rising market that is a large drag. Change the chip and watch both the win rate and the median gap move.
This backtest assumes it earns nothing, which is the assumption that flatters dollar-cost averaging least. If your cash earns interest, the real gap is smaller than the median gap shown here by roughly that yield applied to the money still waiting — over a 12-month spread, that is the yield on about half the amount for about half the year.
This backtest shows what happened to a real price series and nothing more. It excludes trading costs, spreads, currency conversion and tax, assumes cash waiting to be invested earns nothing, and cannot tell you what the next window will do. It is information, not investment advice.
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