This varies by country, but e.g. in Finland IBANs completely replaced legacy numbers in 2010. Mine is 5 characters longer than the legacy number was (added "FI

This varies by country, but e.g. in Finland IBANs completely replaced legacy numbers in 2010. Mine is 5 characters longer than the legacy number was (added "FI", 2 check digits, 2 padding zeroes, removed dash), for a total of 18 characters.