Definitions for "Budget Justification"
A clarification of the budget; explains how dollar amounts were determined; not a rationale for the amounts requested.
Narrative providing details on the use of and need for costs presented in an itemized budget. See Modular Grant link for restrictions on budget justifications in some NIH grant applications.
The financial plan of operation that explains how each cost to be charged against the grant is calculated and why the cost is necessary to the project. May sometimes require that a certain percentage of the total cost be provided by the grantee; i.e., "matched".