Originally Posted by
kodyandgracie
For IAD, not knowing if you come into C or D, I wouldn’t be comfortable with anything under an hour. Also, note that IAD has many late afternoon thunder storms in the summer that can throw everything sideways.
echoing Kody, at least 1 hour. Getting between terminals doesnt typically take more than 10 minutes. But you should build in time for delays from your home airport and you probably want/need to arrive at AF gate at least 30 mins before AF departure. If nothing else, you will have time to get a drink/bite to eat at the AF lounge.