Waterfall vs Agile

Two fundamentally different approaches to project management. Understanding their differences helps you choose the right methodology—or combination—for your project.

At a Glance

Waterfall Methodology

The Sequential Phases

Characteristics

• Each phase must complete before the next begins
• Extensive documentation at each phase
• Clear milestones and deliverables
• Changes require going back to earlier phases
• Customer sees product only at the end

Advantages

• Simple to understand and manage
• Clear structure and milestones
• Well-documented process and outputs
• Easy to measure progress
• Works well with inexperienced teams
• Suitable for fixed-price contracts

Disadvantages

• Inflexible to changes
• Late discovery of issues
• No working product until late
• Customer feedback comes too late
• High risk of delivering wrong product
• Testing compressed at the end

Agile Methodology

The Iterative Cycles

Characteristics

• Work delivered in short iterations (sprints)
• Requirements evolve through collaboration
• Working software delivered frequently
• Continuous testing and integration
• Customer involved throughout

Advantages

• Flexible and adaptive to change
• Early and continuous delivery of value
• Regular customer feedback
• Issues discovered early
• Higher customer satisfaction
• Team morale and ownership

Disadvantages

• Requires experienced, self-organising team
• Customer must be available and engaged
• Scope can creep without discipline
• Less predictable timeline/budget
• Documentation may be insufficient
• Not suitable for all project types

Detailed Comparison

Planning Approach

Team Structure

Customer Relationship

Risk Management

When to Use Each

Choose Waterfall When:

• Fixed, well-understood requirements
  • Regulatory or compliance projects
  • Building to an established specification
  • Migration of existing systems
• External constraints requiring predictability
  • Fixed-price contracts
  • Regulatory approval at each phase
  • Hardware dependencies with long lead times
• Limited customer availability
  • Customer cannot participate frequently
  • Formal acceptance process required
  • Multiple stakeholder sign-offs needed
• Specific project types
  • Construction and engineering
  • Manufacturing
  • Large-scale infrastructure

Choose Agile When:

• Evolving or unclear requirements
  • New product development
  • Innovation projects
  • Market-driven features
• Need for speed and flexibility
  • Competitive markets
  • Startup environments
  • Rapid prototyping needed
• Available, engaged customer
  • Product owner dedicated to project
  • Regular access to end users
  • Feedback can be incorporated quickly
• Specific project types
  • Software development
  • Digital product design
  • Marketing campaigns
  • Research and development

Decision Framework

Use this framework to help decide:

Hybrid Considerations

Many organisations blend both approaches:

Learn more: Hybrid Approaches

Common Misconceptions

“Waterfall means no changes allowed”

Changes can happen, but through a formal change control process. The cost of change increases as the project progresses.

“Agile means no documentation”

Agile values working software over comprehensive documentation—but documentation is created when it provides value.

“Agile means no planning”

Agile plans continuously at multiple levels: release, iteration, and daily. Planning is adaptive, not absent.

“Waterfall always fails”

Waterfall works well for appropriate projects. Failures often come from using it where Agile would be better suited.

“Agile is always better”

Neither approach is universally superior. The best choice depends on project characteristics and organisational context.

Related Resources

• Methodologies Overview - Compare all approaches
• Agile & Scrum Guide - Deep dive into Agile
• PRINCE2 Fundamentals - Traditional methodology
• Hybrid Approaches - Combining the best of both