If you’ve been trading for a while, you’ve probably come across the term Swap—one of the hidden costs that beginner traders often overlook. I think swap forex is something you need to understand in depth, because it can eat away at your profits more than you think.

In simple terms, Swap is the interest that accrues from holding an order overnight. It comes from the fact that when you trade EUR/USD, you are “borrowing” one currency to buy another currency. Each currency has its own interest rate. If the interest rate of what you “buy” is higher than what you “borrow,” you may receive a positive Swap. If it’s lower, you have to pay a negative Swap.

For example, suppose EUR has an interest rate of 4% and USD has 5%. If you Buy EUR/USD (buy EUR, borrow USD), you’ll receive 4% but you’ll pay 5%. The difference is -1% per year—meaning it’s a negative Swap. But the broker still adds its own handling fees, so the Swap you actually receive could be worse.

In reality, the importance of swap forex is mostly negative, because brokers need to make money. It’s a cost that isn’t clearly visible, but it’s there, continuously “biting” away at your profits. If you hold positions for months or even years, it can consume a huge amount of your profit.

What beginner traders often miss is the 3-Day Swap, which is calculated as three times the usual rate on one day of the week—normally the night of Wednesday. The reason is that the Forex market closes on Saturday and Sunday, but interest keeps accruing. So the broker has to make up the full calculation. If you hold 1 Lot of EUR/USD and the Swap Long is -8.5 Points, you’ll lose 8.5 USD per night, but on Wednesday night it will be 25.5 USD.

There are two ways to calculate it. If the platform shows Swap in Points (such as MT4, MT5), you need to multiply by the value of 1 Point. If it shows as a percentage (such as Mitrade), multiply the total value of the position by the % rate. That’s it.

But Swap isn’t only about risk—it also offers opportunities. Some people use a Carry Trade strategy: they borrow money at low interest rates (such as JPY) to buy currencies with high interest rates (such as AUD) in order to receive positive Swap every day. The risk is that if the exchange rate moves against you, the loss could wipe out the Swap gains accumulated over many years.

Another alternative is a Swap-Free account (Islamic account) that many brokers offer. This is suitable for Position Traders who hold orders for a long time, because you don’t have to worry about Swap charges. However, the spread is usually wider, or there are other fees to compensate.

Finally, before opening an order, make sure you check the Swap Rate clearly. If you plan to hold for a long time, negative Swap may make trading not worth it. You can usually see it in the Specification on MT4/MT5 or on the asset information page of your trading platform. This topic may seem complicated, but it isn’t hard to understand. Try it first with a Demo account—practice calculating and you’ll start to get the hang of it naturally.