DCA Calculator (Dollar-Cost Averaging)

DCA calculator: what regular buying would have done

Dollar-cost averaging (DCA) means investing the same amount at regular intervals — say $100 of bitcoin every month — instead of one large purchase. Because a fixed amount buys more units when the price is low and fewer when it is high, your average cost per unit ends up below the simple average of the prices you paid. This DCA calculator shows exactly how that plays out for any price series: how many units you would hold, your average cost, the final value and the profit or loss, side by side with investing the same total as a lump sum at the first price.

You can paste real historical prices (from an exchange export or a spreadsheet) or generate a simple simulated series with a trend and random volatility to see how DCA behaves in rising, falling and choppy markets. A chart, a purchase-by-purchase table and a CSV export make the result easy to check. In India the same idea is known as rupee-cost averaging and is how a mutual fund SIP works.

Everything is computed in your browser from the numbers you provide; no prices are downloaded. The results are informational only and not investment advice.

How to use the DCA Calculator

1. Enter the Amount per buy, the Currency and any Fee per buy your exchange charges (as a percentage).
2. Choose Paste prices and paste the price at each purchase date, oldest first — or choose Simulate a series and set the number of buys, start and end price, volatility and a seed.
3. Read the final value, total invested, units, average cost and profit, and how DCA compares with a lump sum.
4. Check the two charts: portfolio value over time, and the price against your running average cost.
5. Scroll the purchase table or press Download CSV to keep the numbers.

DCA Calculator features

The maths behind dollar-cost averaging

Each buy of amount A at price p_i purchases A ÷ p_i units (less any fee). After n buys you hold Σ A ÷ p_i units for n × A invested, so your average cost is n ÷ Σ(1 ÷ p_i) — the harmonic mean of the prices, which is always less than or equal to their arithmetic mean.

Worked example: $100 at prices 10, 20, 5 and 10 buys 10 + 5 + 20 + 10 = 45 units for $400, an average cost of $8.89 even though the average price was $11.25. At the final price of 10 the holding is worth $450 (+12.5%). A $400 lump sum at the first price would have bought 40 units worth $400, so here DCA came out $50 ahead — because the price dipped in the middle.

DCA vs lump sum: when each wins

• In a market that mostly rises, a lump sum invested early usually ends ahead, because more money is exposed to the rise for longer.
• In a market that falls and then recovers, DCA tends to win: it keeps buying cheaply during the dip.
• In a market that falls and stays down, DCA loses less than a lump sum, but it still loses.
• The main benefit of DCA is behavioural: it removes the need to time the market and spreads the regret of a bad entry.
• Simulations with the same trend but different seeds show how much of the outcome is luck of the path — try several.

Related calculators

For staking yield on the coins you accumulate, see the staking rewards calculator; for providing them as liquidity, the impermanent loss calculator. For a single trade’s profit use the crypto profit calculator, and for mutual fund SIPs at a constant assumed return, the SIP calculator. To value one past purchase between two dates, use the bitcoin investment calculator.