Functional requirements of a system or project include which of the following:

The Functional Requirements Specification documents the operations and activities that a system must be able to perform.

Functional Requirements should include:

  • Descriptions of data to be entered into the system
  • Descriptions of operations performed by each screen
  • Descriptions of work-flows performed by the system
  • Descriptions of system reports or other outputs
  • Who can enter the data into the system
  • How the system meets applicable regulatory requirements

The Functional Requirements Specification is designed to be read by a general audience. Readers should understand the system, but no particular technical knowledge should be required to understand the document.


Rapid Functional Requirement Creation


Examples of Functional Requirements

Functional requirements should include functions performed by specific screens, outlines of work-flows performed by the system, and other business or compliance requirements the system must meet. Download an example functional requirements specification or use these quick examples below.

Interface requirements

  • Field 1 accepts numeric data entry.
  • Field 2 only accepts dates before the current date.
  • Screen 1 can print on-screen data to the printer.

Business Requirements

  • Data must be entered before a request can be approved.
  • Clicking the Approve button moves the request to the Approval Workflow.
  • All personnel using the system will be trained according to internal SOP AA-101.

Regulatory/Compliance Requirements

  • The database will have a functional audit trail.
  • The system will limit access to authorized users.
  • The spreadsheet can secure data with electronic signatures.

Security Requirements

  • Members of the Data Entry group can enter requests but can not approve or delete requests.
  • Members of the Managers group can enter or approve a request but can not delete requests.
  • Members of the Administrators group cannot enter or approve requests but can delete requests.

Depending on the system being described, different categories of requirements are appropriate. System Owners, Key End-Users, Developers, Engineers, and Quality Assurance should all participate in the requirement gathering process, as appropriate to the system.

Requirements outlined in the Functional Requirements Specification are usually tested in the Operational Qualification.

Additional Comments

The Functional Requirements Specification describes what the system must do; how the system does it is described in the Design Specification.

If a User Requirement Specification was written, all requirements outlined in the User Requirement Specification should be addressed in the Functional Requirements Specification.

The Functional Requirements Specification should be signed by the System Owner and Quality Assurance. If key end-users, developers, or engineers were involved with developing the requirements, it may be appropriate to have them sign and approve the document as well.

Depending on the size and complexity of the program, the Functional Requirements Specification document can be combined with either the user requirements specification or the design specification.

Frequently Asked Questions about Functional Requirements

Q: What is the difference between a User Requirement Specification and the Functional Requirement Specification?
A: User Requirements describe the end-user requirements for a system. Functional Requirements describe what the system must do.

Q: Can I see an example of a functional specification?
A: We have a sample functional specification for an Excel spreadsheet available for download.

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Alternative Document Names and Acronyms

The following terms or abbreviations are sometimes used: Functional Requirement Specification, Functional Specification, Program Specification, Functional Specs, Functional Spec, FRS, FS. These documents generally serve the same purpose.

Getting the requirements right is the key to the success of any project. Failure to accurately define and document them inevitably results in miscommunication between stakeholders, constant revisions, and unnecessary delays. Studies show that unclear or poorly documented requirements can increase the project timeline and budget by up to 60%.

With the growing popularity of the Agile approach to documentation, some teams have started to neglect documenting requirements – after all, it's "working software over comprehensive documentation", right?

Alas, it's a common misconception, and foregoing proper internal documentation can be particularly damaging when it comes to requirements. In this article, we'll dive deeper into what functional requirements are and why it's vital to document them.

What are functional requirements?

Functional requirements are product features that developers must implement to enable the users to achieve their goals. They define the basic system behavior under specific conditions.

Functional requirements of a system or project include which of the following:

Functional requirements should not be confused with other types of requirements in product management:

  • Business requirements describe the high-level business needs, such as carving a market share, reducing customer churn, or improving the customers' lifetime value.

  • User requirements cover the different goals your users can achieve using the product and are commonly documented in the form of user stories, use cases, and scenarios.

  • Product requirements describe how the system needs to operate to meet the business and user requirements. They include functional requirements and non-functional requirements.

Functional requirements may be captured as part of a product requirements document (PRD) or in the form of a separate functional requirements document (FRD). Here's an example of what such a document may look like in Nuclino, a unified workspace for all your team's knowledge, docs, and projects – create an account and start documenting your requirements in one central place:

Functional requirements of a system or project include which of the following:

Why functional requirements need to be documented

Documenting and aligning on functional requirements has numerous benefits:

  • The stakeholders have a single source of truth. Clearly documented requirements keep all developers, designers, and QA testers on the same page and working towards the same goal, avoiding misunderstandings.

  • Less time is spent in meetings. When the team has a shared understanding and a written record, there is no need for regular meetings. Instead, stakeholders can rely more on asynchronous communication to stay aligned.

  • Projects become more predictable. Detailed, high-quality requirements allow the team to estimate the development time and cost more accurately and develop a product that meets the expectations.

  • Problems can be identified sooner. Thoroughly capturing functional requirements during the discovery phase helps identify errors early on and correct them, saving time and resources.

Functional requirements examples

Functional requirements need to be clear, simple, and unambiguous. Here are some examples of well-written functional requirements:

  • The system must send a confirmation email whenever an order is placed.

  • The system must allow blog visitors to sign up for the newsletter by leaving their email.

  • The system must allow users to verify their accounts using their phone number.

Contrary to a popular misconception, functional requirements are not analogous to user stories, but stories can be a useful tool for deriving requirements with the user in mind. For example:

  • User story: As an existing user, I want to be able to log into my account.

  • Functional requirements:

    • The system must allow users to log into their account by entering their email and password.

    • The system must allow users to log in with their Google accounts.

    • The system must allow users to reset their password by clicking on "I forgot my password" and receiving a link to their verified email address.

Functional vs. non-functional requirements

When capturing product requirements, it's important to distinguish between functional and non-functional requirements.

To put it simply, functional requirements describe what the product should do, while non-functional requirements place constraints on how the product should do it. They can be expressed in the following form:

  • Functional requirement: "The system must do [requirement]."

  • Non-functional requirement: "The system shall be [requirement]."

Functional requirements – as the name implies – refer to specific product functionality. Defining, measuring, and testing them is usually a straightforward task.

On the other hand, non-functional requirements (also known as "quality requirements" or "quality attributes") are more abstract. They impose constraints on the implementation of the functional requirements in terms of performance, security, reliability, scalability, portability, and so on.

NFRs are not themselves backlog items, but they are just as important since they ensure the usability and effectiveness of the entire software system. A transaction that takes 20 seconds to successfully complete may be functional – but it's certainly not usable.

Every functional requirement typically has a set of related non-functional requirements, for example:

  • Functional requirement: "The system must allow the user to submit feedback through a contact form in the app."

  • Non-functional requirement: "When the submit button is pressed, the confirmation screen must load within 2 seconds."

How to write a functional requirements document

There is no universally accepted functional requirements document template, and it's up to you and your team which style and format to follow. However, there are several best practices that apply in most cases.

In the past, most teams used Microsoft Word to create and manage functional requirements. This inevitably led to out-of-date, inaccurate FRDs bouncing around the team's inboxes.

Fortunately, now you have more options to choose from. Select a tool that facilitates collaboration and ensures that everyone always has the latest version to avoid confusion. For example, you could store your requirements in a Google Doc, or better, in your team's documentation tool or internal wiki, which can be easily set up in Nuclino.

Functional requirements of a system or project include which of the following:

While Nuclino can be used exclusively as a documentation tool, it's highly versatile and capable of much more. It offers a variety of ways to structure and visualize your content, including a nested list, a Kanban board, a table, and a mindmap-style graph. This makes Nuclino a great solution for many additional use cases, including project collaboration, sprint planning, asynchronous communication, and more. Nuclino works like a collective brain, allowing you to bring all your team's work together and collaborate without the chaos of files and folders, context switching, or silos.

Functional requirements of a system or project include which of the following:

Make it a collaborative process

Your FRD needs to be a living document, evolving as your project progresses. To ensure that everyone stays on the same page, every stakeholder needs to continuously contribute. Involve your team early on and collaboratively keep the requirements up-to-date.

Be as clear as possible

Well-written functional requirements typically have the following characteristics:

  • Necessary. Although functional requirements may have different priority, every one of them needs to relate to a particular business goal or user requirement.

  • Concise. Use simple and easy-to-understand language without any unnecessary jargon to prevent confusion or misinterpretations.

  • Attainable. All requirements you include need to be realistic within the time and budget constraints set in the business requirements document.

  • Granular. Do not try to combine many requirements within one. The more precise and granular your requirements are, the easier it is to manage them.

  • Consistent. Make sure the requirements do not contradict each other and use consistent terminology.

  • Verifiable. It should be possible to determine whether the requirement has been met at the end of the project.

Unclear or confusing requirements can create as many problems as undocumented ones. The scope of the project becomes fuzzy, leading to missed deadlines, unforeseen costs, and wasted effort. Making sure the requirements are documented in a way that leaves no room for interpretation can help you avoid these and many other issues down the road.

Nuclino: Your team's collective brain

Functional requirements of a system or project include which of the following:

Nuclino brings all your team's knowledge, docs, and projects together in one place. It's a modern, simple, and blazingly fast way to collaborate, without the chaos of files and folders, context switching, or silos.

What are the functional requirements of a project?

Functional requirements are product features or functions that developers must implement to enable users to accomplish their tasks. So, it's important to make them clear both for the development team and the stakeholders. Generally, functional requirements describe system behavior under specific conditions.

What is included in functional requirements?

Functional requirements may involve calculations, technical details, data manipulation and processing, and other specific functionality that define what a system is supposed to accomplish. Behavioral requirements describe all the cases where the system uses the functional requirements, these are captured in use cases.

What are the functional requirement examples from the following requirements?

Functional requirements examples The system must send a confirmation email whenever an order is placed. The system must allow blog visitors to sign up for the newsletter by leaving their email. The system must allow users to verify their accounts using their phone number.

What are the three main points of functional requirements?

Include requirements that detail what the system should not do to cover every scenario. Focus on features the users truly need. Each requirement needs to be testable. Each requirement needs to track back to one of the objectives.