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ShirtMath
— pts · Thread

Fit by measurements, not labels

Your size changes.Your measurements don't.

Scan one shirt you already own. ShirtMath reads its real measurements and finds shirts cut the same way, across every store.

What measuring one shirt gives you

Measure once

One shirt, eight points of measure, recorded in inches.

Compare every brand

The same numbers across every store in the catalog.

Shop only what fits

See how far a garment sits from your fit before you buy.

Matches built around your measurements

Shop by what you wear

Brands that fit differently

A medium is a different garment at every one of them. Browse by the numbers instead.

One photo, straight down, card for scale

One shirt. Better choices everywhere.

  1. 1

    Lay a shirt you like flat

    Put a bank card beside it for scale, then take one photo from directly above.

  2. 2

    We read it in inches

    Chest, shoulder, sleeve, length and four more points, measured off the photo.

  3. 3

    Shop by the difference

    Every product shows how far it sits from your fit, with live links to the retailer.

Fit proof, not guesswork

A size label is a marketing decision. A measurement is not. Put the shirt you own beside the one you are considering, and the difference stops being a guess.

Matched to your garment

Garments that fit like yours

Real garment measurements first. Style preferences second.

0 garments match your measurements

Scan a garment

AI
An AI garment analyst reads your photos. It identifies the garment, measures it flat in inches with a card for scale, and tells you what it could not see. Numbers it is unsure about are flagged for review rather than presented as fact, and anything you correct becomes the value ShirtMath uses. Your photos go to OpenAI for analysis and are not stored there. How the scanner measures →
Guided scan

Measure a garment with your camera

Lay it flat, put a blank card on it for scale, take a photo or two. The AI analyst identifies it and returns its laid-flat measurements in inches.

Step 1

Lay it flat and smooth it out

Hard surface, no wrinkles, sleeves out to the sides. A plain surface that contrasts with the shirt reads best.

Step 2

Add a scale reference

This is what turns pixels into inches. Pick one — a standard card is quickest (it reads the chest), the printed sheet measures the whole shirt.

Use a blank, expired (details covered), gift, or rewards card. Make sure no card number, name, expiration date, security code, or other personal information is visible.

Lay the card flat on the chest. Quick, but only the chest measures reliably — everything else is left blank.

Take the photo

Shoot straight down over the shirt

Whole garment in frame, blank card flat on it, camera parallel to the floor. The AI reads this photo (plus any extra views you add) together.

Last step

Ready to measure

Working

Reading your shirt

  • Checking photo quality and hiding card details
  • AI analyst identifying the garment
  • Reading any visible label
  • AI analyst measuring every point
  • Checking the numbers
Your measurements

Scanned garment

Only the chest came through? A bank card only reads the chest reliably. Print the marker sheet (100% / Actual Size) to measure the whole shirt next time.

Done

Saved

It's in your closet and set as your reference. Now find shirts cut the same way.

Contribute

Add a garment to the database

Every garment you measure earns points and makes the search better for everyone. Photos of the tag and the flat lay are what turn a submission into verified data.

Your account

Closet & contributions

Because this one fits you

My closet

Star the one that fits you best. That becomes your default reference and drives your recommendations.

Badges

Fit alerts

Save a search and get told when a new garment lands within tolerance of it.

Community quality control

Check other people's numbers

Sample queue while the community is small. If you own this garment, measure it and say whether the submitted numbers hold up. Three agreeing measurements move a garment to Verified. Your accuracy builds your trust score.

Real fits, real people

Community

See what people are actually wearing, the exact shirt behind each fit, and the measurements that make it work — then shop the ones cut like yours.

This week’s challenge

Weekly challenge

Measure every black t-shirt you own

Log 5 black tees this week for a 250-point bonus.

Ends in
4d 11h

Leaderboard

How points work

First person to measure a garment+40
New garment with a full set of measurements+25
Second measurement of a garment someone else logged+10
Photo of the care tag+8
Flat-lay photo with a tape in frame+5
Verifying someone else’s numbers+3
Your numbers later confirmed by two other people+15
Numbers disputed and overturned−20
Standards

How to measure

Everything in ShirtMath is a flat measurement, in inches, on a garment laid on a hard surface with the seams smoothed and nothing stretched. One standard, or the database is worthless.

points of measure