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Bitcoin Data GuideBitcoin Reference

Returns & Performance

Cost basis, break-even and why the average is not the whole story

Cost basis is what a position cost. Break-even is the price at which it stops losing money. Both are simple to calculate and easy to misread, because an average entry price conceals the order in which the purchases were made.

2010-2025Source: Coinbase Exchange daily candles; Bitstamp and CoinDesk historical series for 2010-2014Illustrative examples use the published daily price record.

What cost basis means

Cost basis is the total amount paid to acquire a position, including any fees that are treated as part of the acquisition. For a single purchase it is simply the price multiplied by the quantity. For a position built from several purchases it is the sum of those amounts, and the average cost basis is that total divided by the total quantity held. The average is the figure most often quoted, and it is the one that requires the most care.

Work through an example with published prices. An investor buys one bitcoin at $10,000, another at $30,000, and a third at $60,000. The total cost is $100,000 for three bitcoin, so the average cost basis is $33,333.33. If the price is $40,000, the position is worth $120,000 against a cost of $100,000, a gain of $20,000. The average entry price is a useful summary of that position, and it is not a price at which any of the three purchases actually occurred.

That last point is the one that trips people up. An average cost basis is a derived figure, not a transaction. No bitcoin was ever bought at $33,333.33 in this example. The average is a convenient way to summarise a set of purchases, and treating it as though it were a real entry price leads to reasoning that does not hold — for instance, the belief that the position is "safe" once the price exceeds the average, when in fact the first purchase is deeply profitable and the third is deeply underwater at that level.

Break-even after a decline

Break-even is the price at which the position's value equals its cost basis. For a position with a single purchase it is the purchase price plus any fees. For a position with several purchases it is the average cost basis. The arithmetic is trivial; the interpretation is not, because break-even is a statement about the position rather than about the market.

The asymmetry of losses is what makes break-even worth understanding. A position that falls by fifty per cent requires a gain of one hundred per cent to return to its starting value, because the recovery is measured from a smaller base. A position that falls by eighty per cent requires a gain of four hundred per cent. This is not a property of any particular asset; it is arithmetic, and it is the reason deep drawdowns take so long to recover. The recovery time page shows how long that arithmetic has taken in practice.

Averaging changes the break-even calculation in a way that is genuinely useful. An investor who buys at $60,000 and then buys again at $30,000 holds two bitcoin at an average of $45,000. The break-even price has fallen from $60,000 to $45,000, and the position now needs a smaller recovery to stop losing money. That is the mechanism behind dollar-cost averaging, and it is the reason the approach is often described as reducing risk. It does not reduce the risk of the asset falling; it reduces the price at which the position stops losing money.

Why averaging matters, and where it stops

Averaging matters because it converts a single entry decision into a series of smaller ones. An investor who commits everything at one price is exposed to the risk that the price was a peak; an investor who commits in instalments spreads that risk across many prices. The cost of the reduction is that the average entry price will be higher than the lowest price available during the accumulation period, so the best possible outcome is given up in exchange for a narrower range of outcomes.

Where averaging stops helping is when the asset does not recover. Averaging into a position that continues to fall lowers the break-even price and increases the size of the loss in absolute terms. The strategy assumes that the asset will eventually trade above the average, and that assumption is not guaranteed by anything. An investor who averages into a declining position is making a judgement about the asset's future, and the arithmetic of averaging does not substitute for that judgement.

There is also a practical limit that is easy to overlook. Averaging requires capital to be available as each instalment falls due, and it requires the discipline to keep buying while the position is losing money. Both are harder in a deep drawdown than in a calm market, which is precisely when the strategy is most valuable. The lump sum versus averaging page compares the two approaches directly, and the dollar-cost averaging page publishes what steady accumulation has produced over long horizons.

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