The rate on this page is not one the European Central Bank publishes. It quotes every currency against the euro, so what it publishes is the other direction, and the figure here is that number divided into one. The division is exact; what is not exact is inverting a rate that was already rounded.
1 IDR = USD
Reference rate of 2026-08-17, European Central Bank. Cross rate computed from the two euro reference rates. 1 IDR = 0.0000561287 USD.
Calculated. The European Central Bank publishes one reference rate per currency against the euro, so USD against IDR is a division we perform, not a figure the bank quotes. The direct page says the same thing the other way round.
Does inverting a rounded rate introduce an error?
Yes, and it is measurable. Take a published rate of 1.1535: its inverse is 0.8669267…, and rounded to four decimals that is 0.8669. Invert it back and you get 1.153536, not 1.1535. The gap is a few parts per million, invisible on a coffee and worth knowing on a wire transfer.
Why does the rate I am charged differ from this one?
Because a reference rate is a midpoint between what buyers pay and what sellers ask, published for statistical purposes. Nobody trades at it, not even a bank. The gap is the margin, commonly 1 to 3 percent, and a card payment abroad adds its own on top.
Which direction does the market quote?
Market convention names a pair one way and only one way, and it is rarely the way you happen to need. That is a naming habit, not a statement about which currency matters: the two numbers carry exactly the same information.
How often does this figure change?
Once per working day. The European Central Bank publishes around 16:00 CET on TARGET working days, and there is no rate on Saturdays, Sundays or TARGET holidays. On those days this page shows the last published reference and names its date.