The Gearbox Software president said while the actual budget was double the original game, it's effectively around three or four times because the studio didn't have to invent a whole new game.
"Effectively [the budget is] like triple or quadruple, because in Borderlands 1 we had a lot of invention. We had to figure these things out," he told Digital Spy.
Comparing the inventive process to Edison inventing the lightbulb, Pitchford said it was a "very expensive" ordeal.
"He knew he could do that, in the same way we knew what's fun about the RPG is the fun of collecting loot, and levelling up and growing and making choices.
"That's not mutually exclusive with the moment-to-moment fun of a shooter, we knew that, but we hadn't figured out all the details of what that means to put those two things together.
"You fish around in the dark, you try things and they don't work, and you try other things and you learn from what you tried, and build on that."
He continued: "With Borderlands 2 we don't have any of that. We got to be experts at making Borderlands in the act of finishing it, so with Borderlands 2 so all of the effort is spent towards value that the customer sees, not towards fishing around in the dark and making things that don't work that we have to throw away in order to make new things.
"Effectively it's way more than double. It's actually double budget, effectively it's way more."
Borderlands 2 will be available for Xbox 360, PlayStation 3 and PC on September 18 in North America and on September 21 across Europe.
> Read our latest 'Borderlands 2' interview with Gearbox Software
> Read our hands-on preview with 'Borderlands 2'
Watch the latest trailer for Borderlands 2 below: