Why the statement never matches the rate on the day you paid

The day you use the card abroad and the day the transaction reaches your issuer are not the same day. It passes through the merchant, the acquirer and the international network, and the applied rate is set on the day it arrives.

The Credit Finance Association guide puts that gap at 3 to 7 days. How far it can stretch beyond that is not stated in any public source we could verify, so we put no number on it. If the rate moves in between, the bill moves with it.

So a figure worked out with the rate on the day you paid is an estimate, never a final amount. The same is true here. We do not fetch rates, and the result carries a line saying it was produced from the rate you supplied.

If you want the settled figure, copy the applied rate from your statement. The calculator then works backwards through the bill and shows which term took how much.

There is no published rate at weekends or on public holidays, so the previous business day is used instead. A payment on a Friday evening and one on a Monday morning can arrive under the very same rate.

The same gap shows up in refunds. If a payment and its cancellation are received on different days, two different rates apply, and cancelling the identical amount leaves a little behind or returns a little extra in won. The calculator does not judge that for you, but entering each rate separately shows how large the difference is.