How to budget a film ?(debut director)

I'm an aspiring film director. It's easy for budgeting a shortfilm. As most of the things of are own and some things are needed to be rented.

But when I'm going to make a big budget film like a proper high production quality film for a theatrical feature film. It's hard to estimate the budget. And prices or rents are unimaginable.

How to quote a budget to a producer when am going to pitch my story ?