What is rollover?
Forex pairs are interest-rate differentials between two currencies. When you hold a position past the daily settlement (5pm NY), you either earn or pay the difference — that's the swap.
Why it can quietly destroy a position
Holding 1 lot of GBPJPY long for 30 nights at -$8/night = -$240 in carry costs alone, before price even moves. Many retail traders never check swap rates and wonder why their winners are smaller than expected.
Swap-free / Islamic accounts
For Muslim traders, riba (interest) is haram. Most regulated brokers offer swap-free accounts that replace overnight interest with a flat administration fee — usually only after 2-3 free nights. Verify the structure with your broker before opening.
Calculate your swap exposure
Use the ShaFX swap & commission calculator at /tools/swap-commission-calculator to model holding costs before you open the trade.