Budapest is 5 hours ahead of Rio de Janeiro
Best overlap: 8:00 AM to 1:00 PM in Rio de Janeiro is 1:00 PM to 6:00 PM in Budapest.
Plan around 8:00 AM to 1:00 PM in Rio de Janeiro, which is 1:00 PM to 6:00 PM in Budapest, to catch everyone during office hours. A 5-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day. Note that Budapest follows daylight saving while Rio de Janeiro stays put, so the times above drift by an hour seasonally.