A swap, also known as “rollover fee”, is charged when you keep a position open overnight.
A swap is the interest rate differential between the two currencies of the pair you are trading.
It is calculated according to whether your position is long or short.
How to Calculate Swap
For forex, here’s the formula to calculate swap:
Swap = (Pip Value * Swap Rate * Number of Nights) / 10
Trading 1 mini lot or 10,000 units of GBP/USD (long) with an account denominated in USD.
Pip value: $1
Swap (long) rate: -3.3154
Swap fee: (1* -3.3154 * 1) / 10 = -$0.33