Bitcoin dollar-cost-averaging backtest

A buy-and-hold story is easy: "if you'd bought a thousand dollars of Bitcoin in 2014 you'd be a millionaire." The story rarely gets told the honest way, which is that almost nobody actually had the conviction to buy a thousand dollars of Bitcoin in 2014, and the people who did mostly sold by 2016. The realistic version is dollar-cost averaging — putting a fixed amount in every month regardless of price, accepting that some months you bought at the top and others at the bottom, and letting the long arc do its thing.

This tool walks that math for any starting month from January 2014 to today, at any monthly amount. It computes exactly what a disciplined DCA buyer would have ended up with: total cash deployed, current portfolio value, profit in dollars and percent, average per-coin buy price, and the cumulative equity curve plotted against the dollars-in line so you can see when the strategy was underwater and when it pulled ahead.

Why DCA actually works (when it does)

Two effects compound to make the strategy useful, and one phenomenon causes most retail DCA buyers to give up before either kicks in.

The averaging effect. When you spend a fixed dollar amount each month, you buy more BTC when the price is low and less when it's high — the per-coin average price you pay drifts toward the lower end of the range, not the middle. For a strategy that ran from January 2018 (a near-top) through December 2022 (a near-bottom), the average buy price ends up substantially lower than the simple average of the months in between, because the cheap months "bought more". The same effect protects you, statistically, from buying everything at the wrong moment.

The compounding effect. The dollars you put in early have the longest exposure to whatever growth shows up. A $250 monthly contribution from 2017 has done something fundamentally different from a $250 monthly contribution from last year — not because of the dollar amount, but because of how many growth cycles each contribution sat through. The earliest months disproportionately drive the total return, which is why "starting earlier" tends to dominate "investing more".

The give-up effect. This is what kills most DCA strategies in practice. The equity curve plotted against the dollars-in line spends a long time roughly flat or underwater — sometimes years. A 2018 starter spent roughly two years with their portfolio worth less than they'd contributed. A 2021 starter spent eighteen months similarly. The strategy works only for buyers who hold through that flat-to-underwater phase. Most people don't — they pause contributions, or sell — and capture none of the late-cycle widening that makes the math work historically.

What the chart is showing

The grey line is cumulative dollars invested — it climbs in straight monthly steps. The accent line is current portfolio value — it follows price movements at every step, scaled by the BTC stack you've accumulated. When the accent line is below the grey line, you're underwater on cumulative contributions. When it pulls above, your stack has compounded past what you've put in. The vertical gap between them at the right edge is your unrealised profit.

A successful DCA equity curve usually shows long flat stretches near the contribution line, punctuated by sharp expansions during bull-market windows. Backtests over short windows (under three years) often capture only one of those phases and look misleadingly good or bad. Multi-year windows (4-7 years) capture both phases and give a more honest picture of what the strategy delivers.

What the tool doesn't model

Fees. Real exchange purchases cost something — typically 0.1-1% per buy depending on the venue. Across 60 monthly buys at 0.5% each, that's roughly 0.5% of total invested in fees. Material on tight backtests, negligible on multi-year ones.

Taxes. Sell taxes hit only on disposal. Hold-forever DCA doesn't trigger them. If you eventually sell, your tax depends on your jurisdiction and holding period — see the tax framework posts for region-specific notes.

Custodial risk. A buy-and-hold strategy on an exchange is also a buy-and-hold-on-that-exchange strategy. Custodial failures (Mt. Gox, FTX, Celsius) wiped out DCA buyers who were technically right about Bitcoin but custodially wrong about where they kept it. Self-custody is the standard mitigation; not modeled here.

Currency conversion costs. Buying BTC with non-USD fiat adds an FX layer that can cost 0.5-1.5% per purchase. Over multi-year DCA windows, this stacks. Use the crypto-fiat converter hub for live cross-rates if you want to estimate the FX impact.

FAQ