How to Calculate Profit and Loss on Trades

To calculate profit and loss on a trade, multiply the price change by the number of units and subtract your costs. For a long position, profit or loss is (exit minus entry) times units; for a short, it is (entry minus exit) times units. Subtracting fees and slippage turns a theoretical figure into your real, realized result.

What is the profit and loss formula?

Profit and loss (P&L) on a trade is the money you make or lose from a price move on your position. The core formula multiplies how far price moved by how many units you held. For a long position, where you buy first and sell later, you profit when the exit price is above the entry.

Long P&L  = (Exit Price - Entry Price) x Units - Fees
Short P&L = (Entry Price - Exit Price) x Units - Fees

The only difference for a short, where you sell first and buy back later, is that the subtraction flips: you profit when the exit (your buy-back) is below your entry (your sell). In both cases you multiply by units and subtract round-trip fees. Getting the sign right is the most common slip, so anchor on the rule that profit always means the favorable direction for your position. For the mechanics of selling first, see short selling explained.

A worked example (long and short)

Take a long trade first. You buy 100 shares at 50 dollars and sell at 56 dollars, paying 2 dollars total in commissions. The price moved 6 dollars in your favor across 100 shares.

Long P&L = (56 - 50) x 100 - 2 = 600 - 2 = $598 profit

Now a short. You short 100 shares at 56 dollars and buy them back at 50 dollars, again paying 2 dollars in fees. Because you profit when price falls, you subtract the exit from the entry.

Short P&L = (56 - 50) x 100 - 2 = 600 - 2 = $598 profit

Both make 598 dollars because price moved 6 dollars in the direction each position wanted. If the short had instead risen to 62, the result would be (56 minus 62) x 100 minus 2 = minus 602 dollars, a loss. The arithmetic is symmetric; only the favorable direction differs.

How do fees and slippage change the result?

The clean formula gives a theoretical P&L; your real result is smaller because of costs. Three reduce it: commissions, the bid-ask spread, and slippage, the gap between the price you expected and the price you actually got. On the worked example, 2 dollars of commission barely dented a 600 dollar move, but on small, frequent trades these costs dominate.

Slippage deserves special attention because it is invisible until it bites. A market order in a fast or illiquid market can fill several cents away from the quote, and on a short hold that can erase the edge entirely. As Investopedia notes, slippage tends to be worst around news and at the open and close. Scalpers feel it most; longer-horizon traders least. Always subtract realistic round-trip costs before judging whether a strategy is profitable.

Realized vs unrealized P&L

There are two kinds of P&L, and confusing them leads to bad decisions. Unrealized P&L is the paper gain or loss on a position you still hold, measured at the current market price; it fluctuates every tick and is not money in your account. Realized P&L is what you lock in when you close the trade; only then does the gain or loss become actual cash.

The distinction matters psychologically as much as financially. A large unrealized gain can evaporate before you sell, and an unrealized loss is not a real loss until you either close or your thesis breaks. Disciplined traders judge results by realized P&L over many trades, not by the swings of open positions, which is one reason a trading journal records closed-trade outcomes rather than peak paper gains.

How does leverage change P&L?

Leverage does not change the dollar P&L of a price move; it changes what that dollar figure means relative to your own capital. The position's gain or loss is still (exit minus entry) times units, but because you funded only a fraction of the position with your own money, the same dollars represent a much larger percentage swing on your deposit. A 6 dollar move on a position you control with leverage hits your equity far harder than the headline suggests.

Suppose you control a 10,000 dollar position with 2,000 dollars of your own capital (5:1 leverage). A favorable move that produces 600 dollars of P&L is a 6 percent gain on the position but a 30 percent gain on your 2,000 dollar stake. The same 600 dollar loss is a 30 percent hit to your capital. The dollar P&L formula is unchanged; leverage simply magnifies the percentage return, in both directions, on the money you actually put up.

This is why P&L and leverage must be read together. A trade with a modest dollar loss can still be a severe percentage loss on a leveraged account, and on a margin account a large enough loss can exceed your deposit entirely. Always translate a position's dollar P&L back to a percentage of your own capital, not the position size, to see the real impact. Our leverage and margin explained guide covers the full math.

How do you turn P&L into a percentage return?

Dollar P&L tells you the absolute outcome; percentage return tells you how efficiently you used capital, which is what you compare across trades and accounts. Divide the dollar result by the capital committed to the position, then multiply by 100.

Return % = (P&L / Capital in Position) x 100

In the long example, 598 dollars of profit on a 5,000 dollar position (100 shares at 50) is a 12 percent return before fees. Expressing results as percentages, or better, as R-multiples relative to the amount you risked, lets you compare a small trade to a large one fairly and feeds directly into your expectancy math. For the broader companion calculators, see the Bullynx tools hub.

R-multiples deserve a closer look because they normalize results in a way percentages do not. If you risked 100 dollars on a trade (your entry-to-stop distance times your size) and made 300, that is a 3R win regardless of the account size or the position's dollar value. Tracking trades in R lets you compare a small account's trades to a large one's, judge whether your winners are genuinely outrunning your losers, and compute expectancy directly. It is the cleanest language for talking about P&L across different trades and is worth recording alongside the raw dollar figure.