How to put a QR code on a t-shirt

The two things fabric does to a code

Fabric is a hostile print surface for a precision grid, for two reasons:

1. Texture. The knit breaks up fine detail, so small modules blur into the weave. Keep the payload short (low version) and each module at 2.5 mm or larger, at 10 cm print width that means roughly version 4 (33 modules) or below.
2. Drape. A shirt is never flat when worn. The grid curves over the chest, folds at the sides and stretches with movement. Error correction absorbs some distortion, but a code that only scans when the shirt is stretched flat on a table has failed.

Both push the same direction: bigger, simpler, higher error correction (Q or H). The substrate details live in QR codes on fabric, and the full surface spec in QR codes on t-shirts.

Size and placement

• Minimum 10 cm square on the chest. Under the 10:1 distance rule that scans from about 1 m; a natural, non-awkward distance for scanning someone's shirt. Check your own payload with the size calculator.
• Centre chest, the flattest, most stable area. Avoid side seams, sleeves and anywhere that folds when sitting.
• Back prints work for queues and events (people stand behind each other longer than they stand face-to-chest).

Print method comparison

Method	Edge sharpness	Durability	QR notes
Screen print	Excellent	Excellent	Best all-round; solid ink, survives washing
Vinyl (HTV)	Excellent	Good	Razor edges; can crack/peel after many washes: each module is a cut shape, so avoid tiny modules
DTG (direct to garment)	Good	Moderate	Fine for low volume; ink sits in the fibres and fades with washes, re-test over time
Sublimation	Excellent	Excellent	Polyester (or high-poly blends) only; dye is in the fibre, effectively permanent

Dark shirts: don't invert

On a black or navy shirt the instinct is white modules on the fabric. Resist it: light-on-dark codes scan inconsistently across devices, as covered in why light-on-dark codes fail. The reliable pattern is a printed light panel (white or pale rectangle) carrying standard dark modules, with the panel extending far enough to provide the quiet zone on all sides.

Test protocol: worn, moving, washed

1. Print one shirt before any batch.
2. Scan it worn by a person, from 0.5 m and 1 m, standing naturally, not pinned flat. Try an older phone as well as a new one.
3. Have the wearer move, sit, cross arms; scan again.
4. Wash it five times, scan; ten times, scan. This is where DTG and cheap vinyl reveal themselves.
5. Verify the payload once with the validator so the batch doesn't perpetuate a typo.

Encode something worth a shirt's lifespan: a short URL on a domain you control, not a campaign link that dies in a month: the shirt will outlive the campaign.

FAQ

How big should a QR code be on a t-shirt?

At least 10 cm square on the chest. That gives a scan distance of about a metre, keeps modules above 2.5 mm for a short payload, and leaves margin for fabric texture and drape.

What is the best print method for a QR code on a shirt?

Screen printing for batches, sharp edges and wash durability. Vinyl is equally sharp for small runs. DTG works but fades with washing, so re-test scannability over the garment's life. Sublimation is excellent but needs polyester.

Can I put a white QR code on a black t-shirt?

Print a light panel and put dark modules on it instead. Inverted codes fail on a meaningful share of scanners, and a shirt is already a difficult surface without adding polarity problems.

Why does my shirt QR code scan flat but not when worn?

Drape. The grid curves and stretches on a body, consuming error-correction margin. Increase the size, shorten the payload, use error correction Q or H, and test on a wearer before printing the batch.