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Belgian National Number is your birth date, then an increment from 1 to 999 for every baby born that day, then a base-97 checksum.
by sam_lowry_ 3mo ago
Belgian National Number is your birth date, then an increment from 1 to 999 for every baby born that day, then a base-97 checksum.
- andruby 3mo agoNot sure if still the case: odd numbers for males and even numbers for females. This also means a person’s Belgian RRN can change.
- sam_lowry_ 3mo agoYep, but they do not change on sex change, IIRC.
- andruby 3mo agoI wrote a system for a medical lab decades ago and IIRC I did actually have to change some RRN's manually. It's been a while so I'm not 100% sure, but I do think the changes were due to switching gender.
- port11 3mo agoAre there never more than 1k babies born in a day?
- treszkai 3mo agoWith a population of 12M and life expectancy of 80 years (give or take), probably not, as that needs ~400 newborns a day to maintain, and the birth rate is probably well below that, like in most Western countries.
- port11 3mo agoBack-of-the-napkin math supports that, but baby births aren’t uniformly distributed. Well, anyway, I’m sure they thought about it. Thanks for explaining how I got my Belgian ID number!
- deleted 3mo ago[deleted]
- sam_lowry_ 3mo agoFor the curious, there is a lot more about National Numbers in this pdf: https://www.ibz.rrn.fgov.be/sites/default/files/documents/nl/rijksregister/bestand-rr/bestand-RR.pdf https://www.ibz.rrn.fgov.be/sites/default/files/documents/nl...