How to determine profitable rate for hauling

by Manny
(Clearwater, FL)

Is there a formula that owner operators use to calculate if a particular haul is going to make money for the O/O.

Example: Haul from Miami to Jacksonville (pulling miles out of my buttocks) is 500 miles and the shipper (load board)says $400 to haul it. Should we always look at a minimum of a $1 a mile right off the bat?

Thanks for your assistance.