Tools
Average entry price (DCA) calculator: average price and break-even
Enter each add — its price and size — and get the average entry price, total size, a break-even that includes fees, and the result at the current price. Works for longs and shorts.
How the average entry price is calculated
The average price is weighted by size: average = Σ(price × size) ÷ Σ size. Each add pulls the average toward its own price, and the larger the size, the harder the pull.
Example: a long, first buy 100 × 1, second buy 80 × 3. Cost 100 + 240 = 340, size 4, average price 340 ÷ 4 = 85. A plain average of the two prices would give 90, but most of the size was bought at 80.
Break-even with fees
A fee is paid twice: on entry and on exit. If it is charged on the trade value at a rate f, a long breaks even at an exit price of Σ(price × size) × (1 + f) ÷ (Σ size × (1 − f)), a short at Σ(price × size) × (1 − f) ÷ (Σ size × (1 + f)).
In the example, with a 0.1% fee the long's break-even is 340 × 1.001 ÷ (4 × 0.999) = 85.17, not 85. The short's break-even in the same conditions is 84.83: the fee pushes it down.
Result at the current price
A long's unrealized PnL = (current price − average) × size, a short's = (average − current price) × size. At a price of 90 in the example: (90 − 85) × 4 = +20, which is +5.88% of the position cost of 340.
The exit fee is not part of this PnL — the break-even accounts for it.
Averaging does not reduce risk
Adding below your entry pulls the average price and break-even closer, but it also increases size — and the loss if price keeps moving against you. Measure risk on the total size and the total stop, not on the first entry: the position size calculator shows what you risk in the end.
Frequently asked questions
- How do I calculate the average entry price?
- Multiply each buy's price by its size, add the results and divide by the total size. Example: 100 × 1 and 80 × 3 give (100 + 240) ÷ 4 = 85.
- How is averaging a short different from a long?
- The average is computed the same way. The direction of the result and the break-even differ: a short profits below the average price, and the fee pushes its break-even down, while a long's goes up.
- What is break-even with fees?
- The exit price at which the trade's result exactly covers the entry and exit fees. Without fees it equals the average entry price.
- Can I use it for leveraged futures?
- The formula is the same, with position size in coins or contracts as the size. But an add also changes your liquidation price — recalculate it in the liquidation calculator.
- Does the calculator include the exit fee?
- Yes, in the break-even: it is built for a fee on both entry and exit. The unrealized PnL is shown before the exit fee.
Every trade's result, in money and in R
The Trading OS journal computes a trade's result from real entries, exits and fees — in money and in R.
No sign-up: the journal runs in your browser. An account keeps your trades on the server.