Dollar-Cost Averaging Explained Simply | arvy
July 8, 2026
6 min read
- Dollar-cost averaging means investing the same amount every time, regardless of price. When prices are low you automatically buy more units; when they are high, fewer.
- It lowers your average entry price — but only if prices fluctuate. In a steadily rising market it costs you return compared with investing everything immediately.
- Its real value lies elsewhere: it removes the decision. And that is where most investors actually fail — not at selection.
Cost averaging is the most widely misunderstood concept in investing. It is not a trick for beating the market. It is a tool against your own indecision.
Anyone looking into savings plans for the first time runs into the term dollar-cost averaging sooner or later. It is usually sold as an advantage without anyone explaining when it works and when it does not. This article fills that gap.
01The idea in one sentence
You regularly invest the same amount — not the same number of units. That sounds like a detail, but it is the entire mechanism. Because the amount stays constant while the price moves, you buy more units when prices are low and fewer when they are high. Over time your average purchase price ends up below the average of the prices you paid.
The reason is mathematical: a constant amount divided by a fluctuating price produces a harmonic mean, and the harmonic mean is always less than or equal to the arithmetic mean. You do not need these terms — but it helps to know that what is at work here is an arithmetic rule, not a marketing promise.
02A worked example
Take four months at CHF 400 each. The price starts at 100, falls to 80, then to 50, and recovers to 80.
| Month | Price | Invested | Units bought |
|---|---|---|---|
| 1 | 100.00 | CHF 400 | 4.00 |
| 2 | 80.00 | CHF 400 | 5.00 |
| 3 | 50.00 | CHF 400 | 8.00 |
| 4 | 80.00 | CHF 400 | 5.00 |
| Total | Avg 77.50 | CHF 1,600 | 22.00 |
You invested CHF 1,600 and received 22 units. Your average purchase price is CHF 72.73. The average of the four prices is CHF 77.50. You did not earn that 6% difference through timing — you earned it because the plan automatically bought most in the weakest month.
The decisive point: in month three, with the price halved, most people would not have bought. They would have waited. The savings plan bought anyway — and that single purchase carries most of the advantage.
03When the effect does not work
Here is the honest part. Cost averaging needs volatility. If a market simply rises steadily, you buy at a higher price every month than the month before — and you would have done better investing the full amount immediately.
That is not an edge case. Equity markets rise more often than they fall over long horizons. Which is why studies repeatedly find that an immediate lump sum beats staggered investing in roughly two cases out of three, when the money is already available.
So if you have CHF 60,000 in an account and are wondering whether to spread it over twelve months: statistically, investing at once is the better choice. Emotionally, it is the harder one. Both matter — the full trade-off is in Lump Sum or Savings Plan.
04Why a savings plan is still almost always right
The lump-sum statistic answers a question very few people actually face. It assumes a larger amount is already available. For most people it is not. They have an income with something left over each month — and for that money there is no alternative to investing regularly.
Then there is the part that fits poorly into a table: a savings plan prevents mistakes. It invested in March 2020 and in October 2022 without asking how the situation felt. Over decades, that refusal to have an opinion is worth more than any timing advantage. Studies from Vanguard, Morningstar and Dalbar put the return difference between disciplined and emotional investing at roughly 1% to 1.5% a year.
How much that matters is easy to show: at CHF 500 a month over 30 years, a 7% return produces roughly CHF 610,000 while 5.5% produces roughly CHF 457,000. More than CHF 150,000 of difference, from behaviour alone. More on this in Time in the Market Beats Timing the Market.
05How often: monthly, weekly, quarterly?
The shorter the interval, the stronger the smoothing — but the added benefit fades quickly. Moving from quarterly to monthly matters noticeably more than moving from monthly to weekly.
Two things still argue for shorter intervals. First, your money sits in cash for less time. Second, in turbulent phases you capture more price levels. Over 30 years at CHF 500 a month, however, the pure arithmetic advantage of weekly over monthly execution is only about half a percent of the final value — pleasant, but not a reason to choose a provider.
Far more important than the interval is the date. Schedule execution for the days right after your salary arrives. What leaves first does not get spent — and a savings plan that depends on whatever is left at month end will not survive its first expensive month.
06The three most common misconceptions
"Cost averaging protects against losses." It does not. If a market falls persistently you lose money with a savings plan too — just more slowly and at a lower average cost. The only real protection is a horizon long enough to wait out recoveries.
"Cost averaging beats the market." It does not. You receive the market return, less costs. The effect improves your entry price, not the return of the investment itself.
"With a savings plan I never decide anything again." Almost. One decision remains: to keep going. And it comes due precisely when it feels worst.
07Frequently asked questions
What exactly is dollar-cost averaging?
Regularly investing a constant amount regardless of the current price. Because the amount is fixed and the price moves, you accumulate more units at low prices and fewer at high ones.
Does it work with individual stocks too?
Mechanically yes, practically it is riskier. With a broad index, weak phases mean buying the whole market cheaply. With a single stock you may be adding to a company whose price is falling for a good reason.
Does a savings plan make sense when markets are high?
Yes — because nobody knows whether prices are high. Historically, a market at an all-time high has almost always preceded further all-time highs. Waiting for a cheaper entry usually means waiting too long.
Should I pause my savings plan during a crash?
From an investment perspective it is the worst possible moment. That is exactly when the plan buys the most units per franc. Pausing because your budget requires it is fine; pausing out of fear forfeits the most valuable part of the mechanism.
Is dollar-cost averaging the same as a savings plan?
Almost. The savings plan is the tool; cost averaging is what it produces. Any plan investing a constant amount generates the effect automatically — you can also create it manually, but few people sustain that in practice.
Does the effect also work when selling?
Yes, in reverse. Withdrawing equal amounts means selling fewer units at high prices and more at low ones, which works against you. For decumulation, a needs-based staggered approach beats a fixed franc amount.
How long before the effect shows?
It applies from the second purchase onward but only becomes visible across several market cycles. In a calm year the difference from a single purchase is minimal. Its value emerges in volatile phases.
Do I need a minimum amount of wealth for a savings plan?
No. Savings plans exist precisely to build wealth from ongoing income. What matters is that no fixed per-execution fees apply, since those weigh heavily on small amounts in percentage terms.
08Keep reading
Overview
Costs, taxes, fund domicile and everything else regular investing involves.
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This article was written by Thierry Borgeat, co-founder of arvy, and reviewed by Patrick Rissi, CFA, and Florian Jauch, CFA.
Disclaimer: arvy AG is a manager of collective assets authorised by the Swiss Financial Market Supervisory Authority FINMA under Art. 24 of the Collective Investment Schemes Act (CISA). This article is for information purposes only and constitutes neither investment advice nor tax or legal advice, nor an offer or solicitation to buy or sell financial instruments. The calculations shown are model calculations based on the stated assumptions and are not forecasts; they assume a constant return compounded monthly at the stated nominal annual rate. Past performance is not a reliable indicator of future results. Equity investments are subject to price fluctuations; losses up to the total loss of the capital invested are possible. Tax consequences differ by canton and by individual situation — please clarify yours with a professional.
