June 2, 2023   / Uncategorized

Time and Materials vs Fixed Price – Which One to Choose?

time and materials vs fixed price
5 minutes Read

Choosing the appropriate contract type is crucial to successful software development projects, fostering effective collaboration between clients and development teams. Two popular contract types in this industry are fixed price and time and materials contracts, each with its characteristics, advantages, and considerations. We will explore their differences and when to use each in software development projects.

What is a Fixed Price Contract?

Fixed price contracts are agreements in which both the client and development team agree on a set price for the entire scope of a project, regardless of any changes or unanticipated events during development. They’re often chosen when detailed requirements and specifications exist for such endeavours.

What Is a Time and Materials Contract?

Time and materials contracts involve paying for both actual time and materials spent on a project and their costs, which allows for greater flexibility with project scope changes, iterations processes and design changes during its creation process. Time and materials contracts tend to be used when project requirements are not fully defined upfront.

Fixed Price vs. Time and Materials Contract

1. Project Scope

  • Fixed price contracts necessitate a clearly outlined project scope; any changes or additions may incur extra costs.
  • Contrastingly, time and materials contracts allow for evolving needs and iterative development processes.

2. Cost Control

  • Fixed price contracts allow for cost certainty as prices are pre-set in advance.
  • Time and materials contracts offer more nimble cost management by charging clients only for time or resources used.

3. Risk Allocation

  • Under fixed price contracts, the development team assumes all risks for meeting the budget.
  • Time and materials contracts share this responsibility between the client and team.

4. Change Management

  • For fixed price contracts, any alterations to project scope requires formal change request procedures.
  • While time and materials contracts allow more fluid changes without extensive administrative procedures.

5. Pricing Structure

  • In a fixed price contract, the price is predetermined and remains unchanged throughout the project.
  • A time and materials contract involves payment based on actual time spent and resources used, allowing for flexibility in cost.

6. Advantages and Disadvantages

Fixed Price ContractCost predictability, clear project scope definition, reduced administrative effort, and lower risk to clients are hallmarks of success for any successful endeavour.Limited flexibility for changes, potential disputes over scope, and risks to the development team in case of unexpected complications are all considerations that must be addressed when creating software applications.
Time and Materials ContractFlexibility for evolving requirements, iterative development, increased collaboration, and adaptability to changing project needs are hallmarks of success for successful project delivery.Cost uncertainty for clients, potential challenges in estimating project duration estimates and an active dialogue and trust relationship between the client and development team all present unique opportunities and risks for development teams.

When to Choose a Fixed Price Contract

A fixed price contract is typically suitable under the following circumstances:

Well-Defined Project Scope

Fixed price contracts may be an ideal solution when project requirements are well-documented and unlikely to undergo significant modifications, with both parties having an in-depth knowledge of its objectives, deliverables and timelines.

Cost Predictability

For clients who desire a predictable budget for their project, fixed price contracts offer cost certainty and can help ensure no unexpected cost fluctuations occur. With predetermined pricing structures, clients can plan their finances without incurring unexpected financial strain.

Limited Scope Change Flexibility

Fixed price contracts typically require projects with more definite and stable project scopes, where any changes or scope modifications will be carefully managed through formal change request processes. Such arrangements can be useful if significant scope modifications aren’t expected during their duration and formal change request processes are in place for managing them. In such instances, fixed-price contracts can be suitable options.

Reduce Risk for Client

Fixed price contracts place more risk on development teams. Clients benefit from knowing the costs associated with their project up front and holding development teams accountable for fulfilling agreed-upon scope within budget constraints.

Waterfall or Traditional Development Model

Fixed-price contracts work well with waterfall or traditional development models where project requirements are thoroughly planned and documented before beginning development.

However, while fixed price contracts offer cost predictability, they may have less flexibility for accommodating changes and require a more comprehensive planning phase to accurately define project scope.

When to Consider a Time and Materials Contract

A time and materials contract is generally suitable under the following circumstances

Evolving or Uncertain Project Requirements

If the project requirements are unpredictable or not fully defined in advance, a time and materials contract provides the necessary flexibility. It allows iterative development while adapting the scope as new insights or needs emerge.

Agile Development Approach

Time and materials contracts work well with agile development methodologies such as Scrum or Kanban. Both methodologies emphasize collaboration, frequent iterations, and adaptive planning, making a time and materials contract an excellent option for projects using this framework.

Flexibility for Iterative Development

If the client anticipates their project will change over time or requires regular feedback and iterations, a time and materials contract provides enough flexibility for continuous improvements based on user input or market demands.

Unexpected Challenges May Arise

If there is a high likelihood that unexpected complications, technical challenges, or external factors might impact the direction of a project, time and materials contracts can be highly beneficial in helping both development team members, and clients address and navigate these obstacles together.

Client Engagement and Collaboration

Time and materials contracts involve active client involvement throughout the development process, with regular communication among parties involved and the ability to offer input and make adjustments during its progression. They’re ideal if clients prefer closer involvement, regular updates and flexibility during project development.

Time and materials contracts offer considerable flexibility; however, their cost predictability can present unique challenges for clients. Clients must closely manage their project budget, as the final cost will depend on how much time and resources have been invested.


Selecting between fixed price and time and materials contracts in software development depends on several variables, including project scope, requirements clarity, flexibility needs, risk allocation, and project objectives. Each contract type offers advantages and disadvantages; selecting the ideal one requires carefully considering both the nature and objectives of your project. Effective communication and teamwork between the client and development team are critical to ensure project success regardless of the selected contract type.

FAQs on Fixed Price vs Time and Materials Contract

1. Which cooperation model should I choose for a fixed-price contract?

Waterfall or traditional development models that outline clear requirements upfront often work best with fixed-price contracts.

2. Which cooperation model is commonly utilized with time and materials contracts?

Agile development methodologies like Scrum or Kanban are frequently implemented as time and materials contracts due to their iterative approach and focus on collaboration.

3. Can changes in project scope be managed within a fixed-price contract?

Any modifications to the scope of a fixed-price contract often necessitate a formal change request process. Before proceeding with any proposed modifications, clients and development teams must negotiate and agree upon additional costs and timelines associated with those scope changes before continuing.

4. Can a fixed-price contract accommodate unexpected complexities or technical challenges?

Fixed price contracts usually assume that project scope and requirements are clear and won’t change significantly during its execution; if, however, unexpected complexities or technical challenges emerge, both development teams and clients may need to negotiate additional costs or adjust project specifications as necessary.

5. How are costs calculated under a time and materials contract?

Costs in a time and materials contract are calculated based on both actual time developers spend on the project and costs incurred from materials utilized (if applicable). Clients generally pay an hourly or daily rate for developers’ time and reimbursement expenses related to any materials utilized (i.e. reimbursement expenses).

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