T-shirt Sizing for Design Projects
T-shirt sizing is a project estimation and capacity planning tool that helps you track how much time or effort an initiative will take. It should help in planning timelines for one pagers. To do this, you assign each project or task a t-shirt size—from XS to XL—to represent that project’s relative effort. The T-shirt size should be noted in project tracking tools as well.
Size Definitions
XS (Extra Small)
- Type of work: Small fixes or additions to existing products
- Design: 1 designer for 0 → 1 day
- Engineering: 1 engineer for less than 1 sprint
- Research: Not expected
- One pager: Not expected
- Kickoff: Not expected
S (Small)
- Type of work: Small, net new feature or sizable change to an existing feature
- Design: 1 designer for 1 → 3 days
- Engineering: 1 engineer for less than 1 sprint
- Research: Internal prototyping
- One pager: Expected
- Kickoff: Not expected
M (Medium)
- Type of work: New feature or significant change to an existing feature
- Design: 1 designer for 3 → 5 days
- Engineering: 1 engineer for 1 sprint
- Research: User testing, potential user research
- One pager: Expected
- Kickoff: Expected
L (Large)
- Type of work: Sizable new feature or redo to an existing flow
- Design: 1 designer for 5 → 10 days
- Engineering: 1 engineer for 1 → 2 sprints
- Research: User testing, expected user research
- One pager: Expected
- Kickoff: Expected
XL (Extra Large)
- Type of work: Significant new feature or redo of several flows
- Design: 1 designer for 10 or more days
- Engineering: 1 engineer for 2 or more sprints
- Research: User testing, expected user research
- One pager: Expected
- Kickoff: Expected
Estimation Process
1. Project Breakdown
- List key deliverables
- Identify components
- Note dependencies
- Consider constraints
2. Size Assessment
- Review complexity
- Check dependencies
- Consider unknowns
- Account for reviews
3. Team Discussion
- Share initial sizes
- Discuss differences
- Reach consensus
- Document rationale
Usage Guidelines
When to Use
- Sprint planning
- Resource allocation
- Roadmap planning
- Capacity planning
- Project proposals
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