AvgIn

Dollar-Cost Average Calculator

Add each buy — see your true average cost, total invested, and current paper profit at today's price.

Your buys

Current market price

Candle height = amount invested · green = bought at or below your average cost, red = above

Unrealised profit

$406.96

27.13% ROI

Average cost basis: $29,890.51
Total invested: $1,500
Units owned: 0.05
Current value: $1,907

What you entered

Buys: 3Current price: $38,000.00

1
Total invested across 3 buys
$500.00 + $500.00 + $500.00= $1,500.00
2
Total units bought (amount ÷ price, summed)
$500.00/$30,000.00 + $500.00/$26,000.00 + $500.00/$35,000.00= 0.050183
3
Average cost basis
$1,500.00 ÷ 0.050183 units= $29,890.51
4
Current value at today's price
0.050183 × $38,000.00= $1,906.96
5
Unrealised profit
$1,906.96 − $1,500.00= $406.96

Result

Unrealised profit: $406.96

Your average cost basis of $29,890.51 is below today's price of $38,000.00 — spreading purchases out over time smooths out the effect of buying at any single peak or dip.

How dollar-cost averaging changes your average price

Each row invests $500 four times at the prices listed, then values the position at a current price of $120. Buying a fixed dollar amount purchases more units when the price is low, which is why the average paid is below the simple average of the prices in every volatile row.

Prices paid	Average price paid	Units held	Value at $120	Profit or loss	ROI
100 / 100 / 100 / 100	$100.00	20.000	$2,400	$400	20.0%
80 / 100 / 120 / 140	$105.33	18.988	$2,279	$279	13.9%
150 / 120 / 90 / 60	$93.51	21.389	$2,567	$567	28.3%
200 / 150 / 100 / 50	$96.00	20.833	$2,500	$500	25.0%
50 / 75 / 100 / 125	$77.92	25.667	$3,080	$1,080	54.0%

Look at row four: prices of 200, 150, 100 and 50 have a simple average of $125, but the average actually paid is $96.00, because the same $500 bought ten times as many units at $50 as at $200. That gap is the entire mechanism, and it is why a falling market during the accumulation phase is not the disaster it feels like. The effect is arithmetic, not magic - it does not protect you from an asset that never recovers, and in a market that only rises, investing a lump sum immediately beats spreading it out. Fees per transaction eat into the benefit if you buy very frequently in small amounts.

Why DCA works

Buying the same dollar amount on a schedule means you automatically buy more shares when prices drop and fewer when they rise. Your average cost ends up below the simple price average — a free mathematical edge against volatility.

DCA vs lump sum investing

Studies show lump-sum investing beats DCA about two-thirds of the time (because markets trend up, so investing earlier captures more upside). But DCA reduces the risk of investing a lump sum right before a crash. For money you have now, lump sum is statistically better. For ongoing income, DCA is the natural approach.

How to calculate average cost basis

Add up total dollars invested across all purchases, then divide by total shares/units purchased. If you bought 10 shares at $50, then 15 shares at $40: total invested = $500 + $600 = $1,100, total shares = 25, average cost = $44.00 per share. The average cost is NOT the average of $50 and $40 ($45).

Frequently asked questions

What is dollar-cost averaging?

DCA means investing a fixed dollar amount at regular intervals (weekly, monthly) regardless of price. You automatically buy more shares when prices are low and fewer when prices are high. It removes the stress of trying to time the market and reduces the impact of volatility.

How do I calculate my average cost basis?

Average Cost = Total Amount Invested ÷ Total Shares Owned. Example: bought 100 shares of AAPL at $150 ($15,000) then 50 shares at $130 ($6,500). Total invested: $21,500, total shares: 150. Average cost = $21,500 ÷ 150 = $143.33 per share.

Does DCA work for crypto?

Yes — crypto's extreme volatility actually makes DCA more valuable. Bitcoin has had 50–80% drawdowns multiple times. DCA through those crashes buys heavily at low prices, dramatically lowering your average cost. Many crypto investors set up automatic weekly or monthly buys on their exchange.