Contracts

What is a fixed-price contract in construction?

A fixed-price contract is an agreement where the contractor builds a defined scope for a set price, regardless of what the work actually costs, with changes handled by change order.

A contractor and plan reviewer discuss drawings and permit paperwork across an office desk.
Keep plans, permit requirements and approvals together when preparing construction work. AI-generated illustration.

A fixed-price contract sets the price up front. If the job costs less than planned, the contractor keeps the difference as extra profit. If it costs more, the contractor absorbs the loss. The price changes only through change orders for changed scope or conditions the contract allows for. In private construction this is usually called a lump sum contract or stipulated sum.

Federal contracting uses the term firm-fixed-price. FAR 16.202-1 describes it as a price not subject to adjustment based on the contractor's cost experience, which puts maximum risk and full responsibility for costs, and the resulting profit or loss, on the contractor.

How a fixed-price contract works on a real job

A roofing contractor signs a $268,000 fixed price to reroof a warehouse. The estimate carried $214,000 in cost and $54,000 for overhead and profit.

Example: three ways the same fixed-price job can end
ScenarioActual costContract priceGross profit
Crew beats production rates$198,000$268,000$70,000
Goes to plan$214,000$268,000$54,000
Wet deck found, owner refuses to pay, no unit price in contract$247,000$268,000$21,000

The third row is the lesson. Wet insulation is a classic hidden condition. If the contract had included a unit price per square foot for deck or insulation replacement, the roofer would have billed it as a change. Without one, it depends on whether the contract's differing site conditions clause covers it, and that turns into an argument. Either way, the roofer should stop, photograph the deck, notify the owner in writing, and price the repair before tearing off more.

When fixed price fits, and when it does not

  • Fits: complete drawings, well-understood scope, a contractor with good cost history on similar work.
  • Fits: owners who need a firm number for financing or approvals.
  • Risky: renovation with unknown existing conditions, early design, or volatile material prices.
  • Risky: long schedules without an escalation clause.

Common mistakes and disputes

  1. Bidding scope that is not defined. Every ambiguity becomes either a fight or a gift to the owner.
  2. No exclusions or clarifications in the proposal, so the owner reads the scope as broadly as possible.
  3. Treating extra work as included because nobody wrote a change order. Get approval first.
  4. No unit prices or allowances for the unknowns that will obviously show up.
  5. Front loading the schedule of values. It may help cash flow, but it creates overbilling and erodes trust.

Related terms

Compare with cost-plus, GMP, unit price, and time and materials contracts. Job costing matters most on fixed-price work, because the margin is whatever cost control leaves behind. Smart Business Automator's job costing and WIP views show where a fixed-price job stands each week.

Frequently asked questions

Is a fixed-price contract the same as a lump sum contract?

In everyday construction use, yes. Both mean one set price for a defined scope. Federal contracts use the term firm-fixed-price.

Can a fixed price change?

Only through the contract's change process: owner-requested changes, differing site conditions, and any adjustment clauses such as escalation.

Who carries the risk in a fixed-price contract?

The contractor carries the cost risk for the defined scope. The owner carries the risk of its own changes and, usually, of design adequacy.

Do subcontractors usually work fixed price?

Most subcontracts are fixed price for their scope, sometimes with unit prices for measurable quantities.

Sources

  1. Acquisition.gov: FAR 16.202-1, Firm-fixed-price contracts description
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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