methodatlas
Agile

T-Shirt Sizing

Turns backlog, sprint work, and team flow into a tangible result by explaining the scale, choosing reference items, and marking large items.

Core question
Which size class does each item fall into relative to our references, and which items are so large that they must be cut before planning?
LowWorkshop + async15-45 min
Open runsheetPlan sessionStart comparison
Purpose

The method helps clarify backlog, sprint work, and team flow in a concrete way. It sorts work by value, risk, and delivery capability. The result is captured as size buckets, a rough backlog map, and split candidates.

How it works

The team follows the steps: explain the scale, choose reference items, sort items relative to one another, clarify disagreement briefly, and mark large items. Each step is captured visibly. At the end, size buckets, a rough backlog map, and split candidates are available so decisions, tests, or actions can follow directly.

Visual orientation

Method sketch for a quick mental model.

T-Shirt Sizing · Rough Order of MagnitudeDeliberately sort items imprecisely from XS to XL, use references, and mark large items for slicing
T-Shirt SizingThe visual shows a T-shirt size axis from XS to XL, reference items, placed items, and a split candidate.Create an early size signal without false precisionItems are compared relatively; XL is not an exact value, but a signal for slicing, discovery, or clarification.relative size axisexplain scale firstcompare items relativelyflag large itemsXSsmallSmanageableMnormalLlargeXLneeds slicingStory AEpic BFeature CReference itemknown size for calibrationno hoursdeliberately rough, relative, and earlySplit candidateXL means clarify or slice

Flow

  1. 1Explain the scale
  2. 2Choose reference items
  3. 3Sort items relatively
  4. 4Clarify disagreement briefly
  5. 5Mark large items

The runsheet guides execution with 4 phases, timeboxes, 5 pitfalls, and clear stop criteria.

Open runsheet

Ideal for

  • Epic sizing
  • Roadmap triage
  • Early backlog review

Not good for

  • Detailed planning
  • Contract effort
  • Items with a hard deadline

Deep dive

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.

Output artifacts
Size BucketsRough Backlog MapSplit Candidates
Tags
estimationagileroadmap

Sources

T Shirt Sizing: Agile Estimation & Capacity Planning [2026] • Asanaasana.comAgile Estimating and Planning [Book]oreilly.com
Artifact templates
T-Shirt Sizing Working TemplateCompact working template for T-Shirt Sizing with context, input, output artifacts, and next step.
canvas

t-shirt-sizing-working-template.md

Compact working template for T-Shirt Sizing with context, input, output artifacts, and next step.

T-Shirt Sizing Canvas

Context

What is this method used for?

Core question

Which question should be answered at the end?

Input

Which data, observations, or materials are available?

Working area

  • Area 1:
  • Area 2:
  • Area 3:
  • Relationships / patterns:

Output artifacts

  • Size Buckets:
  • Rough Backlog Map:
  • Split Candidates:

Open questions

  • ...

Next step

Owner, date, success signal.

When to choose differently

Short decision aid for existing alternatives.

Bucket System

Statt T-Shirt Sizing, wenn ihr viele Items in grobe Größenklassen einteilen wollt, ohne jedes einzeln zu schätzen.

Ideal Days

Statt T-Shirt Sizing, wenn ihr Aufwand in reinen Arbeitstagen ausdrücken wollt und Teamkalibrierung beherrschbar halten möchtet.

Similar methods

All methods
Agile
Planning Poker

Turns backlog, sprint work, and team flow into a tangible result by presenting the item, clarifying questions, and discussing deviations before estimating again.

Agile
Bucket System

Moves backlog, sprint work, and team flow toward a concrete result through "prepare buckets and scale", "place reference items", and "flag large or unclear items".

Statt T-Shirt Sizing, wenn ihr viele Items in grobe Größenklassen einteilen wollt, ohne jedes einzeln zu schätzen.

Agile
Ideal Days

Moves backlog, sprint work, and team flow toward a concrete result through "explain the ideal day unit", "calibrate with a reference item", and "do not confuse it with calendar days".

Statt T-Shirt Sizing, wenn ihr Aufwand in reinen Arbeitstagen ausdrücken wollt und Teamkalibrierung beherrschbar halten möchtet.

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

Turns backlog, sprint work, and team flow into a tangible result by preparing items as cards, building a relative size axis, and clarifying outliers and uncertainties.

Agile
Scrum

Product Backlog, Sprint Goal, Increment, and retrospective loops create a repeatable cadence for complex product work.