An Unallowable Cost is one that cannot be charged to a sponsored Award. Refer to the Award itself or sponsor-specific regulations for unallowable costs.
For Federal Awards, review the Award document, the Program Announcement, the funding agency regulations, and the Code of Federal Regulations (CFR, see below) for information on unallowable costs. For information on the hierarchy of these requirements go to the Federal Regulation Hierarchy Pyramid.
The CFR Subpart E. “Cost Principles” provides detailed information on specific costs including if specific circumstance or cost attribute determine if a cost is allowable or not.