$2 a gallon. 50% increase means $3 a gallon.

$4 a gallon 25% increase means $5 a gallon.

Both a flat $1 increase. The large differences in nationwide gas prices don't really apply to the increase we are feeling from the Iran war. The price is basically increasing flat across the board because the other differences are remaining constant but the cost of a barrel is still increasing by the same amount everywhere.

My 2 cents though. Someone feel free to tell me I'm wrong.