Glossary
Unit price contract
A unit price contract sets a price for each unit of a defined item of work. The solicitation lists estimated quantities, bidders price each line, and the bid total is the sum of quantity times unit price. Payment follows actual measured quantities, so the final contract value moves up or down with field conditions.
It is the standard structure where quantities cannot be known precisely in advance (excavation, paving, pipe, striping, tree removal, snow plowing, testing services) and it is the pricing basis for job order contracting.
The short version
- Award is decided on the extended total using the agency's estimated quantities, but you are paid on actual quantities.
- That gap creates unbalanced bidding, which most public agencies now police explicitly.
- Every line must be priced. A blank or zero line is a common responsiveness problem.
- Major quantity variations, often defined as more than 25 percent from the estimate, typically trigger a price adjustment clause.
Why it matters to a bidder
Unit pricing rewards estimators who understand the agency's quantity takeoff as well as their own costs:
- Verify the quantities. If the estimate for a line is materially wrong and you can show it during the question period, an addendum correcting it protects everyone including you.
- Do not front-load. Loading early-occurring items to improve cash flow, or loading lines you believe are underestimated, is unbalanced bidding. Agencies check for it and can reject the bid as materially unbalanced.
- Watch mobilization caps. Many specifications cap mobilization at a small percentage of contract value precisely to prevent front-loading.
- Read the variation clause. Know what happens if an item runs at 40 percent of the estimate. Some contracts allow renegotiation of the unit price, others do not.
A real example
A county lets a drainage improvement contract with an estimated 900 cubic yards of rock excavation. One bidder prices rock at four times the market rate and offsets it by underpricing common excavation, betting the rock quantity will overrun. The extended total is competitive and it wins. Actual rock comes in at 2,400 cubic yards. The county pays roughly triple its estimate for that item. On the next project it adds an unbalanced-bid review and a quantity-variation clause, and rejects a similar bid as materially unbalanced.
How state and local differs from federal
Both federal and state work uses unit pricing, but the volume and the standardization sit at the state level. State departments of transportation are the largest users, and each publishes standard specifications with defined pay items, measurement methods and quantity-variation rules. Those documents are public and reused across every project the agency lets, so they are worth reading once and applying for years. The measurement method for a pay item often matters more to your margin than the unit price itself.
Local governments frequently adopt their state DOT's standard specifications by reference, which means a city street project may be governed by a specification written for highways. Check what the contract incorporates. Federal unit-price work under the FAR relies more on contract-specific clauses and less on a standing published specification.
Common questions
How is the low bidder determined?
By the extended total using the agency's estimated quantities. Actual payment then follows measured quantities.
What is unbalanced bidding?
Pricing some line items well above or below cost to exploit expected quantity variations or to improve early cash flow. Materially unbalanced bids can be rejected.
What if a quantity changes dramatically?
Most specifications contain a variation clause, often triggered around a 25 percent change, allowing an adjustment to the unit price for that item.
Do I have to bid every line?
Yes. A blank or zero-priced line is usually treated as nonresponsive or as a commitment to perform that item at no cost.