A currency swap is a financial instrument that is used for rolling over an open forex position to the next trading day. A swap fee/income is charged or gained when you keep a position open overnight. The swap fee or income is calculated from the difference in market interest rates between the two currencies of the currency pair you have an open position.
The swap charge or income will be credited or debited accordingly once every end of day for the period that you hold an open position. The swap rates can change on a daily basis according to the movements in market interest rates. Spikes in market interest rates can result in considerable changes in the daily swap rates. The TFI swap calculator can be used to calculate the swap fee or income attributable to a currency pair for a specified period of time.
TFI Markets calculates swap once for each day of the week that a position is rolled over.
On Wednesday night the swap is charged 3 times to account for the weekend, except for the USDRUB, EURRUB and USDCAD instruments where the swap is charged 3 times on Thursday night instead of Wednesday night.
Number of lots x swap points = amount in the counter currency of the pair
EURGBP 2 lots long, eurgbp swap long= -5.08
2 x (-5.08) = -10.16 GBP