Originally Posted by
cyog
What is a safe amount of time to leave for a transfer at IAD airport if I'm arriving from DOH on QR and looking to fly AC to yyz?
I would allow no less than 4 hours.
You will have to clear immigration and customs on arrival then check-in, then go through security then get to your gate for the connecting flight. Immigration and customs times at IAD is frequently atrocious due to habitual (purposeful?) understaffing during rush hour.
If you are arriving during the morning rather than the afternoon rush, 4 hours ought to be enough but I would still build in more time.