Dollar-cost averaging bitcoin: how DCA works

Dollar-cost averaging (DCA) means buying bitcoin for the same amount of money at regular intervals — say 50 dollars every week — whatever the price. You buy more when the price is low and less when it is high, so you never have to decide when the right moment is. DCA settles when to buy. Whether to buy is a separate question.

How the arithmetic works

Because the amount is fixed, the quantity changes. A toy example: you spend 100 when the price is 10 and get 10 units, then 100 when the price is 20 and get 5 units. You spent 200 for 15 units, an average cost of about 13.33 — below the average of the two prices, which is 15. With a fixed amount per buy, your average cost always lands at or below the simple average of the prices you bought at, because the cheap buys bring in more units.

What DCA does and does not do

• It removes timing. You do not need to know whether today is a good day to buy.
• It smooths the entry. A single buy at a high is the worst case of a lump sum; spread over a year, no single day decides your price.
• It does not protect against a falling market. If the price falls for the whole period and stays down, every buy loses money. DCA only changes the price you pay.
• It is not guaranteed to beat a lump sum. If the price rises steadily through your DCA period, money invested all at the start would have bought more. If it falls, DCA comes out ahead. Neither can be known in advance.

Choosing the amount and interval

A common approach is an amount you can keep buying for years without needing the money back, and an interval that matches your income, usually weekly or monthly. The interval matters less than sticking to it: a plan abandoned in the first long decline turns DCA into buying high and stopping low. It helps to decide in advance what you would do if the price halved.

Fees can eat a small DCA

A fixed fee on each buy hurts small amounts most: a 1-dollar fee on a 20-dollar buy is 5% of it. Check the exchange's fee for recurring buys against its regular trading fee, and if the fees are large, buy less often with more each time. When you move the coins to your own wallet, batch withdrawals rather than withdrawing after every buy, since each one pays a network fee — see network fees explained.

Tracking a DCA stack

A year of weekly buys is 52 transactions per exchange, and each needs its price and fee for your average cost to be right. Export the history as a CSV now and then rather than copying buys by hand (Binance, Coinbase, Kraken), and let a tracker compute the average. The formulas are in how to calculate crypto profit.

Nothing on this page is investment advice. DCA is a way of buying, and whether to buy at all is your decision.

This guide explains how things work. It is not financial, investment or tax advice. Something wrong? Write to hi@perly.io and we will correct it.