FAR 15.501—Definition.
Plain-English Summary
FAR 15.501 is a short definitional provision in the negotiated procurement subpart. It does not create a new substantive rule; instead, it tells readers that the term “day,” as used in this subpart, has the meaning given in FAR 33.101. Its purpose is to ensure consistent counting of time periods wherever the subpart uses deadlines, response periods, or other time-based requirements. In practice, this means contracting officers, offerors, and contractors must look to FAR 33.101 for the controlling definition rather than assuming that “day” means a calendar day, business day, or some other measure. This cross-reference matters because time calculations can affect proposal submissions, discussions, notices, and other procedural rights and obligations under Part 15. The section is brief, but it is important because misunderstanding the definition of “day” can lead to missed deadlines, disputes over timeliness, or procedural errors in source selection actions.
Key Rules
Cross-reference controls meaning
The term “day” in this subpart is not independently defined here. Users must apply the definition found in FAR 33.101 whenever the word appears in Subpart 15.5.
Uniform time counting
The provision promotes consistent interpretation of all time periods in this subpart. This helps avoid different counting methods for the same term across procurement actions.
Read with the cited definition
Any deadline or timing requirement in this subpart must be read together with FAR 33.101. Parties should not substitute their own understanding of what a “day” means.
Responsibilities
Contracting Officer
Apply the FAR 33.101 definition when calculating any time period in this subpart and ensure solicitations, notices, and communications use the term consistently.
Contractor/Offeror
Use the FAR 33.101 meaning of “day” when determining response deadlines, submission dates, or other timing obligations under this subpart.
Agency
Maintain consistent internal guidance and training so personnel interpret and apply the term “day” uniformly in negotiated procurement actions.
Practical Implications
Always check FAR 33.101 before counting days under this subpart; do not assume the term means calendar days or business days.
A timing mistake can cause a late proposal, missed clarification response, or an invalid procedural challenge.
Contracting officers should avoid ambiguous drafting by clearly stating deadlines and ensuring they align with the FAR definition.
Contractors should verify deadline calculations immediately upon receiving a solicitation amendment, discussion notice, or other time-sensitive communication.
Official Regulatory Text
Day , as used in this subpart, has the meaning set forth at 33.101 .