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.