What Makes a Cost Reasonable Under FAR 31.201-3: A Quick Guide for Estimators
Pricing work on federal construction projects requires estimators to understand how the government reviews proposed expenditures. Whether you are assembling initial pricing proposals or pricing change orders during performance, federal regulations establish specific standards for whether a contractor's figures can be accepted. The core standard governing this review is defined in FAR 31.201-3 Determining reasonableness. Understanding how the regulation defines acceptable pricing protects your bids from unexpected government challenges.
The Prudent Person Rule in Competitive Business
Under FAR 31.201-3, a cost is classified as reasonable if, in both its nature and its amount, it does not surpass that which a prudent person would incur while operating a competitive business. This baseline applies across all pricing submissions, from direct trade line items to project overhead and general conditions estimating.
The regulation evaluates two distinct aspects of every cost:
- Nature of the cost: Whether the expenditure itself represents a logical, standard expense appropriate for the project or enterprise.
- Amount of the cost: Whether the financial quantity charged stays within sensible market bounds rather than inflating beyond competitive commercial levels.
The Burden of Proof and the Lack of Presumption
A central reality of federal contracting is that no automatic presumption of reasonableness attaches to any cost incurred by a contractor. Estimators and project managers cannot assume that merely billing or incurring an expense makes it justifiable in the eyes of the government.
If an initial examination of facts causes either the contracting officer or the contracting officer representative to question or challenge a specific figure, the burden of proof falls entirely upon the contractor. The contractor must supply sufficient evidence and rationale to verify that the questioned cost satisfies the competitive, prudent-person standard.
Circumstances and Considerations That Govern Reasonableness
Reasonableness cannot be judged in a vacuum; it relies upon diverse considerations and context. The regulation outlines key circumstances that govern whether a particular expenditure holds up to scrutiny:
- Ordinary and necessary status: Whether the item is recognized generally as an ordinary and necessary cost to operate the contractor business or execute contract performance.
- Sound commercial practices and regulatory compliance: Alignment with generally accepted sound business customs, true arm's-length bargaining, and applicable federal and state laws and regulations.
- Broad professional responsibilities: The obligations the contractor carries toward the government customer, commercial clients, company owners, personnel, and the general public.
- Deviations from standard operations: Any noticeable departures or significant variations from the contractor established historical operating practices.
Heightened Scrutiny in the Absence of Competition
The regulation instructs federal personnel to apply elevated scrutiny in certain organizational setups. Specifically, contracting authorities must examine costs with particular care when evaluating firms or separate company divisions that may operate outside effective competitive restraints.
When estimators work within entities or specialized corporate branches where regular competitive market pressure is reduced or absent, cost justifications receive heightened inspection. In these environments, estimators must be doubly thorough in establishing that the nature and financial extent of the pricing reflect what an arm's-length, prudent buyer would pay.
How Estimators Can Defend Their Federal Pricing
To successfully establish that pricing meets the regulatory test, estimators must align their proposal narratives and backup details with the factors contracting officers evaluate. If challenged, an estimator must be prepared to demonstrate that:
- The expense stems from arm's-length dealings with reputable suppliers and lower-tier trade partners.
- The rate or expenditure mirrors standard company accounting and does not represent an arbitrary departure from long-standing operational methods.
- The scope of work or administrative effort is truly necessary for contract completion or core business operations.
- The resulting figure reflects sound commercial judgment that protects the interests of both the project and the government.
Sources
Acquisition.GOV: FAR 31.201-3 Determining reasonableness
Published October 31, 2026. No affiliate links on this page. Facts come from the sources linked above; check them for updates.