What is PnL? Profit and loss explained for stock investors
PnL (profit and loss, also written P&L) is the running scorecard of a position or portfolio. The number that matters is not the peak unrealised gain, it is the PnL you actually lock in when you exit.
Key takeaways
- PnL, P&L and P/L all mean profit and loss: current value minus what you paid.
- Unrealised PnL moves with the market; realised PnL is only fixed when you sell.
- Fees, spreads and currency conversion all belong in an honest PnL figure.
- Protecting PnL means deciding how much open gain you will give back before you exit.
PnL in one sentence
PnL is short for profit and loss. For a single stock position it is simply what the position is worth now minus what it cost you. If you bought 10 shares at $50 and the stock trades at $65, your PnL is 10 × ($65 − $50) = $150, or +30% on the $500 you invested. Traders write it as PnL, P&L or P/L; they all mean the same thing.
Realised vs unrealised PnL
Unrealised (or “open”) PnL is the paper gain or loss on a position you still hold. It changes every time the price moves. Realised PnL is what you lock in when you sell: once the trade is closed, that profit or loss is fixed. The gap between the two is where most investor regret lives, a large open gain that is never realised can shrink back to nothing.
How to calculate PnL per position
Per share, PnL is the current price minus your average cost. Multiply by the number of shares for the position total, and divide by your total cost for the percentage. If you bought in several lots, use the weighted average cost rather than your first purchase price. For a portfolio, sum the PnL of every position; for a return figure, divide by the total amount invested.
What an honest PnL includes
Headline PnL often ignores costs. Commissions, FX conversion fees on foreign shares, and the bid-ask spread all reduce what you actually keep. If you hold US stocks in a UK or EU account, currency moves also change your PnL: a stock can rise in dollars while your gain shrinks in pounds or euros. Track PnL in the currency you will eventually spend.
Why unrealised gains need a plan
An open gain is only a number on a screen until you act on it. Without a pre-decided exit, investors tend to hold through reversals hoping the peak returns, and hand back profit they had already made. Deciding in advance how much of the open PnL you are willing to give back, and where that exit sits, is what turns a paper gain into money you keep.
Where the name PnLock comes from
PnLock is short for PnL Lock: tools for locking in profit and loss decisions before emotions take over. Profit Lock compares volatility-aware exit levels for each position, Portfolio Analytics shows where your PnL is concentrated, and Reentry Intelligence helps you decide when to put realised gains back to work. It is decision support: you place any order yourself.
Common questions
What does PnL stand for?
PnL stands for profit and loss. You will also see it written as P&L or P/L. In investing it means the gain or loss on a position or portfolio.
Is unrealised PnL real money?
Not yet. Unrealised PnL is a paper figure that changes with every price move. It only becomes realised, fixed, when you sell the position.
How do I lock in PnL without selling everything?
Common approaches are a stop order at a level you choose, a trailing stop that rises with the price, or selling part of the position. The level should reflect the stock’s normal volatility so routine noise does not trigger it.
Is PnLock related to Pinlock or PopNLock?
No. PnLock (PnL Lock) is an investing tool for portfolio risk and exit planning at pnlock.app. It is unrelated to visor inserts, door locks or other similarly named products.
Profit Lock
Profit Lock helps investors turn an open position into a clear exit plan. It compares several stop models, grades the quality of each level, and shows the risk before you make a manual decision.