Been getting a lot of questions about PnL lately, so figured I'd break down what is PnL and why it actually matters for your crypto trading.

Look, if you've traded stocks or traditional finance, you probably know the basics. But crypto PnL has some nuances that trip people up. Essentially, PnL is just measuring whether you made or lost money on your positions. Simple as that. But here's where it gets interesting - there's realized PnL (money you actually locked in by closing a trade) and unrealized PnL (paper gains/losses on positions you still hold). Understanding the difference changes how you think about your portfolio.

Mark-to-market (MTM) is the foundation of all this. It's just valuing your holdings at current market price. Say you bought ETH yesterday at $1,950 and today it's at $1,970 - that $20 difference is your daily PnL. Nothing fancy, just the price difference.

Now, realized PnL is what you actually locked in. If you bought Bitcoin at one price and sold it at another, the difference between entry and exit is your realized PnL. This is real money. Unrealized PnL is different - it's the profit or loss on positions you haven't closed yet. Still holding that ETH? The difference between your entry price and current price is your unrealized PnL.

When it comes to calculating PnL, there are a few methods traders use. FIFO (first-in, first-out) assumes you sell the oldest coins first. LIFO (last-in, first-out) assumes you sell the most recent purchases first. And there's the weighted average method, which calculates your average cost across all purchases. Each method can give you different results, which is why tax season gets complicated.

Here's a practical example: Say you bought 1 BTC at $30,000, then another at $40,000. Using weighted average, your cost basis is $35,000. If you sell at $50,000, your profit is $15,000. But if you used LIFO, you'd be selling the $40,000 one first, so your profit would be $10,000. Same position, different methods, different outcomes.

For perpetual contracts, you need to track both realized and unrealized PnL together since you never actually close the position - you just maintain your margin. Add them up to get your total PnL on perps.

The real lesson here? Understanding what is PnL and how to calculate it properly keeps you grounded. You can track your actual performance, see which strategies work, and make better decisions next time. A lot of traders just guess, but if you're actually measuring your PnL, you're already ahead of most people. Use spreadsheets, trading bots, whatever helps you stay organized. The traders who win are the ones who actually know their numbers.