How much extra fuel should I put on a flight from Dubai to Boston?
Depends on what aircraft you’re flying/fuel burn
If you are flying one of the newer (and/or reworked) aircraft, I would take 1.5-2h extra.
If flying one of the older aircraft (747, etc…), take around 3h extra…
I recommend using a flight planner an simply set the amount of extra fuel: Infinite Flight FPL Converter
90 minutes extra plus a diversion airport which would be JFK most likely. I would recommend using sim brief
I will be flying a 777.
Use about 1.5hr but it also depends on you wether it be altitudes , speeds and wind
1:30 extra gate to gate or time in air?
In-air, even though taxing uses very little fuel compared to in-flight…
The legal requirement is 30 min of fuel after your planes ETA