About the Dollar Cost Averaging Calculator
This dollar cost averaging (DCA) calculator shows what regular, fixed-amount investing really achieved. Enter the amount you invest each time, the share or coin price at each purchase and today’s price. It returns your average cost per share, total shares, current value, profit and percentage return.
Because a fixed amount buys more shares when prices are low and fewer when they are high, your average cost (before fees) is always at or below the simple average of the prices you paid. The calculator shows both so you can see the effect, and compares your result with investing the whole amount at the first price (lump sum).
It works for stocks, ETFs, mutual funds and crypto on any schedule — weekly, monthly or per paycheck. Enter one price per purchase, separated by commas, spaces or new lines (no thousands separators). An optional per-trade fee is subtracted from each purchase.
With the default inputs, the average cost per share is $101.03. Change any value above to recalculate instantly.
How to use the dollar cost averaging calculator
- 1Enter the fixed amount you invest at each purchase.
- 2List the price you paid at every purchase, oldest first.
- 3Enter today’s price and any per-trade fee.
- 4Read your average cost, profit and return, then compare with the lump-sum figure.
Formula and method
Each purchase buys (amount − fee) ÷ price shares. Your average cost per share is everything you spent (including fees) divided by the total shares you own. Because the same dollar amount buys more shares at lower prices, this average is the harmonic mean of the prices, which is never higher than the ordinary average.
Current value is total shares × today’s price, and the return compares that value with the total invested. The lump-sum comparison invests the same total at the first purchase price, with a single fee, so you can see whether spreading purchases out helped or hurt over this specific price path.
- A
- Amount invested at each purchase
- Pᵢ
- Price at purchase i
- N
- Number of purchases
- P_now
- Current price
Worked examples
$500 a month for a year while the price dips and recovers
Twelve $500 purchases between $85 and $120 bought 59.39 shares at an average cost of $101.03 — below the $102 simple average of the prices. At $120 they are worth $7,126.63, an 18.78% return. Because the price ended well above the first purchase, a lump sum at $100 would have done slightly better at $7,200.
Buying through a crash: $1,000 at 50, 40, 30, 25, 30, 40
Buying steadily as the price halved gave 176.67 shares at an average cost of $33.96. At $45 they are worth $7,950 — a 32.5% gain — even though the price is still below the first purchase. A lump sum at $50 would be worth only $5,400.
Rising market with a $1 fee per trade
Six $250 purchases (each $249 after the fee) into a steadily rising price bought 60.91 shares at an all-in average cost of $24.63. At $31 they are worth $1,888.30, a $388.30 profit.
Frequently asked questions
What is dollar cost averaging?+
Dollar cost averaging means investing a fixed amount at regular intervals — for example $500 every month — regardless of the price. You automatically buy more shares when prices are low and fewer when they are high.
Is DCA better than investing a lump sum?+
Vanguard’s studies of historical US, UK and Australian market data found that investing a lump sum immediately has beaten DCA roughly two-thirds of the time, because markets tend to rise. DCA reduces the risk of investing everything right before a drop and can make it easier to stay invested.
Why is my average cost lower than the average price?+
With a fixed dollar amount you buy more shares at low prices, so low prices carry more weight. Mathematically your average cost is the harmonic mean of the prices, which is always less than or equal to the arithmetic mean.
Does dollar cost averaging work for crypto?+
The math is identical for Bitcoin, Ethereum or any asset. Crypto’s larger price swings make the gap between your average cost and the simple average price bigger, but it does not guarantee a profit if the price falls and stays down.
Is contributing to a 401(k) every paycheck dollar cost averaging?+
Yes. Investing the same percentage of each paycheck into a 401(k) or IRA is a form of DCA, and it is the main way most people invest.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.