Been thinking about how many crypto traders don't actually understand their own PnL, and honestly it's wild. Like, you can be making or losing money but not really know what that means or how to calculate it properly.

So what does PnL means in the first place? Basically it's just profit and loss—the change in value of your positions over time. Sounds simple, but there's actually a lot more depth to it than just checking if you're up or down.

The foundation starts with mark-to-market (MTM), which is just valuing your assets at current market price. Say you're holding ETH and it was $1,970 today but $1,950 yesterday—that $20 difference is your PnL for that period. Pretty straightforward.

But here's where it gets interesting. There's realized PnL (what you actually locked in by closing a position) and unrealized PnL (profits or losses on positions you're still holding). These are totally different things and traders often confuse them. If you bought DOT at $70 and it's now at $105 but you haven't sold, that $35 gain is unrealized. Only when you actually sell does it become realized.

Now, calculating PnL means you've got options depending on your situation. The FIFO method (first-in, first-out) uses your earliest purchase price. Say you bought 1 ETH at $1,100, then another at $800, and sold at $1,200—FIFO would use that $1,100 as your cost basis, giving you a $100 profit. But LIFO (last-in, first-out) would use the $800 price instead, showing a $400 profit on the same trade.

Then there's the weighted average cost method, which splits the difference. If you bought 1 BTC at $1,500 and another at $2,000, your average cost is $1,750. Sell at $2,400 and you're looking at a $650 profit. Different methods, different outcomes—which one you use actually matters for your tax situation too.

Most casual traders just track open and closed positions. You open a position when you buy, close it when you sell. Buy 10 DOT at $70, sell at $100, your PnL is $30. Simple math, but doing this consistently gives you real insight into your trading performance.

For people holding long-term, year-to-date (YTD) calculations are useful. If you held $1,000 worth of ADA on January 1st and it's worth $1,600 now, that's $600 in unrealized gains. No cash yet, but you know where you stand.

Here's the thing though—these are all simplified examples. In real trading, you've got fees, taxes, funding rates on perpetual contracts, market volatility. Understanding what PnL means is the foundation, but actually calculating it in practice requires accounting for all those variables.

If you're serious about trading, especially with perpetuals where you can hold positions indefinitely, you need to track both realized and unrealized PnL together to get your total picture. There are tools and bots that can help automate this, but knowing the mechanics yourself makes you a better trader. You can actually assess whether your strategy is working or if you need to adjust.

The traders who really level up are the ones who regularly review their trades, understand their cost basis, and know exactly where their profits or losses are coming from. That knowledge shapes better decisions going forward.