Direct answer
Forex gain or loss is calculated by turning a currency price move (the difference between entry and exit price) into money, then scaling it by the trade size. In practice, you compute a position’s price-based profit or loss (often expressed with pips), and then adjust for any additional costs that your platform treats as part of the trade result (for example, commissions and overnight financing). What you finally call “net” depends on which components are included in your reporting.
Mechanics: from price movement to money
A forex position is defined by:
- Direction: long (buy) or short (sell).
- Entry and exit: the prices at which the position opens and closes.
- Contract size / units: how much of the base currency is controlled by the position.
- Price move: the difference between exit and entry.
Step 1: convert the price move into pips (if your system uses pips)
Many traders and platforms express moves in pips. A pip is a standardized unit of price change for a currency pair. Because pairs have different decimal conventions, the exact pip size depends on the pair. For calculation, you need the pair’s pip definition used by your platform.
Step 2: convert pips to monetary value (pip value)
To translate pips into account currency, you use pip value, which depends on:
- the pair traded,
- the position size (contract size), and
- the conversion rate needed when your account currency differs from the pair’s quote.
A simplified way to express the relationship is:
- Price-based P&L (money) = (number of pips moved) × (pip value per pip)
Step 3: apply direction
If you are long, a favorable price increase produces positive P&L; if you are short, the sign flips. The calculation’s magnitude stays the same for the same absolute price move and size, but the sign changes with direction.
Step 4: compute “net” by including costs the platform charges
Reported results often include more than price movement. Common components are:
- Commissions or spreads (how the platform represents execution and transaction costs), and
- Overnight financing / swap (costs or credits for holding a position across certain time boundaries).
So you may see:
- Price-based P&L (from movement) differs from net P&L (movement plus financing and other trade costs).
Example and independent checks (conceptual)
Assume you have a position with a known contract size and a platform-defined pip value. To verify your understanding:
- Note the entry price and exit price (or the platform’s reported pips moved).
- Confirm the pip-to-money conversion by checking your platform’s pip value for that trade size.
- Multiply the pips moved by pip value to estimate price-based P&L.
- Compare your estimate to the platform’s profit/loss number and account for any reported commissions, fees, or overnight financing.
If the platform shows both “pips” and “profit/loss,” you can use this comparison as an internal consistency check without needing any external data.
Limitations and risks of misunderstanding
- Different reporting definitions: “profit,” “P&L,” and “net result” may include different components depending on the platform and instrument.
- Pair-specific pip rules: pip size and decimal placement vary by currency pair, so applying a generic pip rule can create calculation errors.
- Conversion and pip value complexity: when account currency differs from the pair’s pricing currency, pip value depends on conversion inputs used at the time.
- Averages are not single-trade formulas: in an average win/loss context, you compute each trade’s net result first, then summarize across trades. Average win and average loss describe distributions and may hide the timing and cost differences across trades.