Purpose
When effort only needs to be classified roughly, it makes comparability more important than false precision. It helps sort work quickly into manageable sizes.
Agile Decision method
T-Shirt Sizing
Sorts backlog items roughly by reference sizes and flags topics that later need splitting or clarification.
T-shirt sizing places work into a small number of size classes and focuses on relative scale rather than fine-grained precision. It creates a quick shared reference for planning and discussion while details are still emerging.
Which rough relative size class describes each comparable item using shared anchors without false precision or hidden point conversion?
- Participants
- 2-12
- Time
- 30–60 minutes for 10–25 comparable items; recalibrate when work mix changes.
The practice is repeated across comparable work items.
Scope
Comparison frame
Set item set, sizing dimension, and Definition of Done across all sizes.
Anchors
Size anchors
Choose one known item per size and explain the order through actual work.
Sort
First sort
Place items silently relative to anchors; use XS/XL only for clear differences.
Clarify
Calibrated sizes
Discuss boundary cases and different placements through scope, risk, and dependencies.
Close
Sizing view
Split or clarify oversized/unknown items; save sizes, anchors, and assumptions for later calibration.
Add new evidence at review and version decisions with the prior state.
A good fit when
Wenn Aufwand nur grob eingeordnet werden soll, macht sie Vergleichbarkeit wichtiger als Scheingenauigkeit. Sie hilft, Arbeit schnell in handliche Größen zu sortieren.
Ideal for
- Epic sizing
- Roadmap triage
- Early backlog review
Not good for
- Detailed planning
- Contract effort
- Items with a hard deadline
Outputs
Sizing view
Relatively ordered items in XS/S/M/L/XL with anchors, boundary assumptions, clarification pile, and split rule for oversized work.
T-Shirt Sizing · working structure
Fictional example
Fictional values show the actual method fields.
| Item | Included work | Comparison anchor | First placement | Boundary assumption | Final size | Follow-up |
|---|---|---|---|---|---|---|
| Delete tokenAdd evidence and rationale. | Build, test, security, rollout | S · validate billing address | S | Existing endpoint; no migration path | S | Ready |
| Save cardAdd evidence and rationale. | Build, test, security review, rollout | M · save provider token | M/L | M without guest users and migration; otherwise L | M | Fix scope in item |
| Card managementAdd evidence and rationale. | List, default card, delete, failure paths | L · new payment method | L | One provider; no migration | L | Ready |
| Provider migrationAdd evidence and rationale. | Auth, migration, fallback, certification | Larger than L anchor | XL | Several independent outcomes | XL | Split into three items |
1. Included work
- Delete token
- Build, test, security, rollout
- Save card
- Build, test, security review, rollout
- Card management
- List, default card, delete, failure paths
- Provider migration
- Auth, migration, fallback, certification
2. Comparison anchor
- Delete token
- S · validate billing address
- Save card
- M · save provider token
- Card management
- L · new payment method
- Provider migration
- Larger than L anchor
3. First placement
- Delete token
- S
- Save card
- M/L
- Card management
- L
- Provider migration
- XL
4. Boundary assumption
- Delete token
- Existing endpoint; no migration path
- Save card
- M without guest users and migration; otherwise L
- Card management
- One provider; no migration
- Provider migration
- Several independent outcomes
5. Final size
- Delete token
- S
- Save card
- M
- Card management
- L
- Provider migration
- XL
6. Follow-up
- Delete token
- Ready
- Save card
- Fix scope in item
- Card management
- Ready
- Provider migration
- Split into three items
All values are fictional.
First step
Set a comparable item set and included work; select XS–XL scale and stable reference items from the team's own experience.
Deep dive
How it works
It places tasks into a few size classes and directs attention to ratio rather than pinpoint precision. This creates a quick shared yardstick for planning and conversation, even though details only sharpen later.
In detail
T-Shirt Sizing uses familiar size classes to roughly order effort, complexity, or uncertainty. Teams compare items relative to one another instead of promising absolute hours or days. The method is especially useful when there is not yet enough detail for story points or concrete effort values. Large sizes signal that scope should be cut or discovery should continue.
Facilitation
Define the scale visibly and calibrate it with one or two reference items. Avoid direct conversion into hours or the method loses its purpose. Mark XL items as candidates for slicing or further clarification.
The method guide walks execution through 5 phases, timing, 5 pitfalls, and clear stop criteria.
Open method guideYour perspective
Does this method help with your work?
Your feedback helps shape the next improvements to methodatlas.
Sources and topics
Topics
In playbooks
Artifact templates
T-Shirt Sizing: WorksheetSet subject, evidence, roles, flow, and review.markdown
T-Shirt Sizing: WorksheetSet subject, evidence, roles, flow, and review.
markdownt-shirt-sizing-working-template.md
Set subject, evidence, roles, flow, and review.
T-Shirt Sizing: Worksheet
Question
To be confirmed
Desired outcome
To be confirmed
Scope
Practice run Time: 30–60 minutes for 10–25 comparable items; recalibrate when work mix changes.
Complete this worksheet on paper or in your own document during the work.
Preparation for this scope
Method setup
- Materials: Comparable items, shared Definition of Done, XS/S/M/L/XL sizes, one reference item per size, and clarification pile
- Roles: Delivery team estimates · product owner clarifies · facilitator calibrates · experts answer questions
- Advance information: Set a comparable item set and included work; select XS–XL scale and stable reference items from the team's own experience.
- Overall time needed: 30–60 minutes for 10–25 comparable items; recalibrate when work mix changes.
- Setup: Prepare a workspace with Scope · Anchors · Sort · Clarify · Close; separate example from live data.
Prepare for the work steps
Scope: Comparison frame
- Set a comparable item set and included work; select XS–XL scale and stable reference items from the team's own experience.
- Comparable items, shared Definition of Done, XS/S/M/L/XL sizes, one reference item per size, and clarification pile
Anchors: Size anchors
- Comparison frame
Sort: First sort
- Size anchors
Clarify: Calibrated sizes
- First sort
Close: Sizing view
- Calibrated sizes
T-Shirt Sizing · working structure
| Item | Included work | Comparison anchor | First placement | Boundary assumption | Final size | Follow-up |
|---|---|---|---|---|---|---|
| Delete token | ||||||
| Save card | ||||||
| Card management | ||||||
| Provider migration |
- Delete token: Add evidence and rationale.
- Save card: Add evidence and rationale.
- Card management: Add evidence and rationale.
- Provider migration: Add evidence and rationale.
The blank worksheet contains prompts only.
Reference · original teaching example
Scope: Comparison frame
Expected artifact: Comparison frame
Set item set, sizing dimension, and Definition of Done across all sizes.
Entry:
...
- Are items comparable and does size include the same work types?
Anchors: Size anchors
Expected artifact: Size anchors
Choose one known item per size and explain the order through actual work.
Entry:
...
- Are anchors from the same context and clearly ordered?
Sort: First sort
Expected artifact: First sort
Place items silently relative to anchors; use XS/XL only for clear differences.
Entry:
...
- Does every item sit between understandable neighbours?
Clarify: Calibrated sizes
Expected artifact: Calibrated sizes
Discuss boundary cases and different placements through scope, risk, and dependencies.
Entry:
...
- Was a size change explained by a different work model?
Close: Sizing view
Expected artifact: Sizing view
Split or clarify oversized/unknown items; save sizes, anchors, and assumptions for later calibration.
Entry:
...
- Does every XL item have a split question and every unclear item an owner?
Open questions and next steps
...
Method guide: https://methodatlas.meierhoff-systems.de/en/methods/t-shirt-sizing/run-sheet
Alternatives and neighbors
Fitting alternatives with decision guidance, followed by other related methods.
Agile
Bucket System
Instead of T-Shirt Sizing, choose Bucket System when you want to sort many items into rough size classes without estimating each one individually.
Agile
Ideal Days
Instead of T-Shirt Sizing, choose Ideal Days when you want to express effort in pure working days and keep team calibration manageable.
Agile
Story Points
Moves backlog, sprint work, and team flow toward a concrete result through "choose reference stories", "define the scale", and "interpret velocity only within the team".
Agile
Affinity Estimation
Has the team group items silently, discusses deviations, and produces consistent relative size pictures.
Agile
Scrum
Product Backlog, Sprint Goal, Increment, and retrospective loops create a repeatable cadence for complex product work.
Agile
NoEstimates
Moves backlog, sprint work, and team flow toward a concrete result through "clarify the planning question", "slice work smaller", and "calibrate regularly with reality".
Constraints and origin
LowWorkshop + async15-45 min
Profile
- Method form
- Decision method
- Participants
- 2-12
- Time
- 15-45 min
- Maturity
- Established
- Origin
- Agile Community
Next up: Story Splitting