Project management
Project contract types: fixed price, time and materials, cost plus
A fixed quote covers an agreed result. An hourly rate covers agreed time. Compare three ways to price the same integration, including the work nobody has defined yet.
A project's contract pricing arrangement sets how the supplier is paid for the agreed work. Fixed price sets a price for defined scope. Time and materials pays agreed rates for time and specified costs. Cost reimbursement pays actual costs that the agreement allows the supplier to charge, with a fee where specified.
These labels do not define the entire agreement. Deliverables, acceptance, responsibilities, limits and changes still need to be clear.
A team buying a warehouse integration has a €24,000 fixed quote and an €80 hourly option. Comparing those two numbers tells it very little until it knows what each covers.
Compare the same assignment before comparing prices
In this fictional example, the integration transfers released shipment records into the finance system. The agreed scope covers one interface, defined fields, error handling and acceptance tests. A possible second interface has not been investigated.
The team estimates 250 hours for the defined work. That estimate is a planning input. It does not become an obligation to finish in 250 hours merely because it appears in a spreadsheet.
| Arrangement | Example payment basis | What the buyer needs to manage |
|---|---|---|
| Firm fixed price | €24,000 for the defined accepted scope | Scope, acceptance evidence and the treatment of changes |
| Time and materials | €80 per approved hour; no materials in this example | Authorised work, rates, hours, deliverables and spending limits |
| Cost plus fixed fee | Eligible actual costs plus an agreed €3,000 fee | Which costs qualify, cost evidence, approvals and the fee terms |
The US Federal Acquisition Regulation, Part 16 gives formal examples of these pricing mechanisms. Its rules apply to US federal procurement; private agreements and other jurisdictions can use different terms. Read the actual agreement rather than inferring its conditions from the label.
What happens if the original work takes longer?
Suppose the same defined integration takes 320 hours instead of 250, with no approved scope change. Under the simplified firm fixed-price example, the price remains €24,000 despite the supplier's extra effort.
Under the hourly example, 320 authorised hours cost €25,600. At 250 hours, they would cost €20,000. Neither comparison includes taxes or other charges.
For cost plus fixed fee, assume the eligible delivery costs are €18,000 and the fee remains €3,000. Payment would be €21,000. If eligible costs become €23,000, the same fixed fee gives €26,000, subject to the agreement's approvals and limits.
The hourly rate includes the supplier's agreed commercial rate. An eligible-cost figure may exclude profit before the separate fee is added. Do not compare €80 per hour directly with an internal cost rate and assume the difference is waste.
Fixed price still needs a change process
The team now asks for the second interface. That is new work outside the defined assignment. The €24,000 price does not settle whether or how it will be delivered.
Assess the additional requirement, the effect on the existing interface, testing and the date. Obtain the agreed approval before treating it as committed work. The scope and change-control example follows that decision in more detail.
Under an hourly arrangement, the extra interface still needs authorisation. Available budget is not permission to build anything the team suggests.
A spending ceiling also needs an operating rule. If the hourly work is capped at €24,000, what must the supplier do when the remaining authorised hours look insufficient? A cap without that review can leave an incomplete result at exactly the approved budget.
Match the arrangement to what is known
Defined, testable scope makes a fixed-price comparison easier to assess. Unresolved technical work may suit a bounded discovery phase before anyone prices full delivery. The choice depends on the supplier market, evidence and the buyer's ability to manage the work.
APM's contract-management overview places the agreement within project delivery. In practice, the project team needs access to the scope, acceptance conditions and commercial decision process throughout the assignment.
If the team cannot explain the second interface yet, start with the requirements-gathering example. Transferring an undefined problem into a fixed-price request does not make the uncertainty disappear; it can return as an exclusion, allowance or later dispute.
Keep payment connected to evidence
Before work starts, agree who can authorise it, what records support payment, how acceptance is shown and when a forecast overrun must be raised. Review the remaining work alongside spending, not after the budget is exhausted.
For this integration, that means following an agreed interface through a tested result. The contract type explains the bill. It does not establish whether the business received the service it needed.
Sources and example notes
- Acquisition.gov: FAR Part 16. Formal US federal definitions of firm-fixed-price, cost-reimbursement and time-and-materials mechanisms.
- APM: Managing contracts in project management. Contract management as project work.
All rates, hours, costs and scope are fictional. The examples explain pricing mechanics rather than propose contract wording. Actual payment and risk allocation depend on the full agreement and applicable rules.