Types of procurement contracts and when to use each

Two companies buy a website build. One signs a fixed price of 40,000 dollars and the scope grows by half. The other signs time and materials and the budget doubles. Each picked a contract type, and each learned who pays when plans change.

That is the heart of the topic. A procurement contract type is a risk allocation decision wearing a legal costume.

Why the contract type matters

Every purchase has two uncertainties: how much the work will cost the supplier and how much the scope will change. The contract type sets who absorbs each. A buyer who understands that can choose deliberately instead of accepting whatever template the supplier sends.

The main types at a glance

Fixed price contracts

The supplier agrees to deliver a defined scope for a set price. If the work costs more, the supplier absorbs it. If it costs less, the supplier keeps the difference.

This gives the buyer budget certainty, and it works well for standard goods and for projects with a detailed specification. It works badly when the scope is fuzzy, because every ambiguity becomes a dispute, and suppliers price in a cushion to cover that risk.

• Use when: the deliverable can be described precisely, such as buying 500 chairs or building a defined module.
• Protect yourself by: writing acceptance criteria, setting a change request process and agreeing how scope additions are priced.

Time and materials contracts

The buyer pays for the supplier's time at agreed hourly or daily rates, plus materials at cost or with a markup. The supplier carries little cost risk and the buyer carries most of it.

These suit work where nobody can specify the full scope in advance, such as discovery projects, support work or early software development. The danger is an unbounded bill.

• Use when: the work is exploratory or the requirement will change as you learn.
• Protect yourself by: setting a not-to-exceed cap, requiring regular timesheets and holding checkpoint reviews.

Cost reimbursable contracts

The buyer reimburses the supplier's actual allowable costs and adds a fee, either fixed or a percentage. Common in construction, defense and research where costs cannot be forecast.

The buyer carries the cost risk. A percentage fee gives the supplier no reason to reduce cost, and may reward the opposite, so many buyers prefer a fixed fee or an incentive that shares savings.

• Use when: the scope is genuinely uncertain and cost cannot be estimated reliably.
• Protect yourself by: defining allowable costs tightly, auditing the books and setting a ceiling.

Unit price contracts

The price is fixed per unit, and the total depends on how many units you buy. Useful for services or materials where quantity is uncertain, such as cubic meters of concrete or minutes of transcription.

• Use when: each unit is the same and you know the rate but not the volume.
• Protect yourself by: adding volume tiers, minimum commitments you can live with and an annual price review.

Framework agreements

A framework agreement sets terms, prices and conditions up front for purchases to be made over a period. It does not commit you to a specific volume. Individual orders, called call-offs, follow the agreed terms.

Public bodies use frameworks heavily. Private companies use them to avoid renegotiating with the same suppliers each time. The advantage is speed. The risk is that a framework left alone becomes stale as the market moves.

Blanket agreements and purchase orders

A blanket agreement sets a value or quantity ceiling for repeat orders from one supplier, with releases made as needed. See blanket purchase order workflow and our purchase order guide.

Retainer contracts

The buyer pays a regular fee for access to a supplier's time or expertise, such as a law firm or a security consultant. Agree what the retainer covers, what happens to unused hours and what extra work costs.

How to choose

1. Ask how well you can describe the work today. If completely, lean toward fixed price. If barely, lean toward time and materials with a cap.
2. Ask how likely the scope is to change. High change favors flexible contracts with a change process.
3. Ask who is better placed to manage the risk. The party closer to the cost drivers should usually carry them.
4. Ask how much oversight you can provide. Cost reimbursable and time and materials need active management.
5. Ask how often you will buy this. Frequent repeat buying justifies a framework or blanket agreement.

Clauses that matter whatever the type

• Scope and deliverables. What exactly is being provided.
• Change control. How scope changes are requested, priced and approved.
• Payment terms. Due dates, milestones and late payment consequences.
• Service levels and remedies. What happens if the supplier misses them.
• Liability and indemnity. Limits and carve-outs.
• Term, renewal and termination. Notice periods, auto-renewal and exit rights.
• Data and confidentiality. Especially for software and services.

Our contract management guide explains how to keep track of these once the contract is signed, and the MSA template and SLA template give you starting points.

Terms you will see in contracts

• Not-to-exceed cap. A ceiling on total spend under a flexible contract.
• Milestone payment. A payment tied to completing a defined stage of work.
• Retention. A portion of payment held back until final acceptance.
• Liquidated damages. Pre-agreed compensation for specific failures, such as late delivery.
• Indemnity. A promise to cover the other party for certain losses.
• Force majeure. A clause excusing performance when extraordinary events outside control occur.
• Termination for convenience. The right to end the contract without cause, usually with notice and sometimes a fee.

Choosing a type when you are unsure

If you honestly cannot decide, use this fallback. Split the work into a small, flexible discovery phase on time and materials with a cap, then use the learning to write a clear scope for a fixed price delivery phase. You get flexibility where uncertainty is high and certainty where it is low.

Related reading

After signing, you need to track what you agreed. See what is contract management. For how contracts fit into the wider buying cycle, read the procurement lifecycle guide.

Frequently asked questions

Where to read next

• What is contract managementAfter the signature
• Purchase ordersThe order document
• Contract approval workflowGetting sign-off
• MSA templateFree download