The Method · est. 8 min read

Dollar cost
averaging,
without the mystery.

A complete primer on the simplest investment strategy that consistently outperforms the people who try to be clever. Read it once, run a backtest, and you'll know more than 90% of retail investors.

· Definition

Dollar-cost averaging is the practice of investing a fixed amount into the same asset at a fixed cadence, regardless of price.

That's it. Three components: an amount, a cadence, an asset. The discipline isn't in the formula — it's in not stopping.

01

You stop trying to time markets

There is overwhelming evidence that retail investors who time the market do worse than ones who don't.

02

You buy more shares when cheap

A fixed dollar amount buys more units when the price is low. Mechanically, this lowers your average cost.

03

Your emotions stop running the show

The decision is made once. After that, you're executing — not deciding. This matters more than the math.

· Worked example

$250/month into SPY for 10 years.

Numbers below are computed from real adjusted-close SPY data at each site build.

Jan 2016May 2026
Total invested
$31,250
125 × $250
Final value
$74,352
+$43,102
Profit
+138%
CAGR 8.7%
Avg buy price
$310.67
SPY: $739.17
Fig. 01 — Portfolio value vs. dollars invested
Value Invested
· The flat-market case

Where DCA really earns its keep.

In a roaring bull market, almost any strategy works. DCA's structural advantage shows up in sideways and choppy markets — exactly the conditions that flush out everyone trying to time the bottom.

This chart shows the same $250/month strategy applied to a flat market with the same volatility. The end result is still profit — because you bought more shares at every dip than you did at the peaks.

Final value
$31,800
Invested
$30,000
Return
+6.0%
in a flat market
Fig. 02 — Same strategy, flat-ish market
· The math

The formula, demystified.

01. Average cost (DCA)
Σ contributions ÷ Σ units bought

Crucially, this is dollar-weighted — buying more when cheap drags it down.

02. CAGR
(end / start)^(1/years) − 1

The constant annual rate that would have grown your principal into the end value.

·
Why this is the right average
A simple arithmetic average of prices would weight each month equally — but DCA weights cheaper months more (you buy more units). The dollar-weighted average reflects what you actually paid.
· Cadence

How often should you buy?

The honest answer: it barely matters. Over 10+ years, every cadence converges. Pick the one you'll actually stick to.

Daily
260
buys / year

Best mathematical fit; only if you can automate it.

Weekly
Best
52
buys / year

Sweet spot. Captures dips, low fee impact.

Bi-weekly
26
buys / year

Works well with biweekly paychecks.

Monthly
12
buys / year

Bare minimum. Smaller dip-capture, simpler ops.

· The fine print

When DCA doesn't work.

01

When the asset goes to zero

DCA into a failed altcoin is just a slow trip to zero. You're only as good as your asset selection.

02

When you stop

Most DCA "failures" are people who quit during the 2022 bear and missed the subsequent run-up.

03

On short timeframes

Anything under 5 years isn't really DCA — it's lump-sum with extra steps and worse expected returns.

04

When fees eat the gains

A $10 weekly buy with a $1 fee is a 10% drag. Use no-fee or low-fee venues.

· Next step

Stop reading. Start backtesting.

Plug in your own amount, frequency, and start date. Compare what could have been with what could still be — both modes, one calculator.

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