Zero Base Budgeting is Where no Profit & No Loss

A method of budgeting in which all expenses must be
justified for each new period. Zero-based budgeting starts
from a "zero base" and every function within an organization
is analyzed for its needs and costs. Budgets are then built
around what is needed for the upcoming period, regardless of
whether the budget is higher or lower than the previous one.

In zbb the budget is made from the scratch, as estimated in case of a new venture. This enables the managers in carrying the cost benefit analysis of individual activities of their respective decision units. This helps in neutralizing the discrepancies in normal budgeting process where sometimes a particular inaccuracy in a previous year’s budget is carried to the next year without evaluating its contribution to performance of the organization.