The swap is calculated based on the interest rate differential between the two currencies in the pair, your position size, and the number of nights you hold the position.

In formula terms (simplified):

Swap = (Pip Value × Swap Rate × Days Held) / 10

The result may be positive (you earn) or negative (you pay) depending on which currency carries the higher interest rate.

Swap rates can vary daily because they depend on changing interest rates, market liquidity, and broker adjustments.

Also, long (buy) and short (sell) positions often have different swap rates due to which currency is being held or borrowed.

Because forex markets are closed on weekends, a triple-swap adjustment is applied once a week to account for Saturday and Sunday. For most forex pairs, this happens on Wednesday night (i.e. the rollover from Wednesday to Thursday).

Essentially, the swap for three nights is charged in one go.

Answer:
Yes — while the swap itself is separate from margin, for long-term positions, repeated swaps (especially if negative) can accumulate significantly and impact your net returns or account equity.

In other words, even if your margin stays sufficient, the swap charges over time might erode profits or amplify losses if you’re not managing them.