Been noticing a lot of traders in the community get confused about how PnL actually works in crypto, so figured I'd break this down since it's honestly fundamental to not losing money.

First thing - PnL (profit and loss) in crypto isn't magic. It's just the difference between what you paid for something and what it's worth now or what you sold it for. But here's where most people mess up: they don't understand the different types.

Mark-to-market (MTM) is basically just valuing your position at current market price. Say you're holding ETH - its value changes every second based on what people are actually willing to pay. That's MTM. Simple enough.

Now, realized PnL only matters when you actually close your position. You buy at $1,900, sell at $2,100 - that $200 profit is realized. Done. Locked in. But if you're still holding and the price dropped to $1,600? That's unrealized PnL - the loss is only on paper right now.

This is actually crucial because a lot of people panic when they see their unrealized losses. But it's not real until you sell.

For calculating actual PnL, there are a few methods depending on how you trade. FIFO (first-in, first-out) assumes you sold the coins you bought first. So if you bought 1 ETH at $1,100, then another at $800, and sold at $1,200, you'd use the $1,100 entry price and make $100 profit. LIFO (last-in, first-out) does the opposite - uses your most recent purchase price, so you'd use $800 and make $400 profit on the same trade. Weighted average cost splits the difference - you average all your entry prices together.

Which one you use depends on your trading style and tax situation, but the math is straightforward once you pick one.

Then there's the practical stuff: monitoring your portfolio performance over time (YTD calculations work great for this), transaction-by-transaction tracking if you're active, or just looking at percentage gains to compare different trades fairly.

If you're trading perpetual contracts - those infinite futures with no expiration - you need to track both realized and unrealized PnL together since you can hold positions forever. Same concept though.

Honestly, the biggest thing I see traders miss is not accounting for fees. These simplified examples don't include trading fees or taxes, but in real trading that stuff adds up fast and eats into your actual returns.

Point is: understanding your PnL breakdown - realized vs unrealized, entry vs exit prices, fees - that's how you actually know if your strategy is working or if you're just gambling. Most people trading without tracking this properly have no idea what's actually profitable. If you're serious about trading, get this down first before anything else.