QR codes on receipts

Receipt printers are 203 DPI direct-thermal devices, so each QR module must be a whole number of dots, in practice a 2–2.5 cm code. Use error correction Q because direct-thermal print fades within weeks in a wallet, and keep the URL short since 58 mm paper cannot fit dense codes.

Typical scan distance	15–25 cm
Minimum code width	2–2.5 cm
Error correction	M–Q

The module arithmetic

Receipt printers are overwhelmingly 203 DPI: 8 dots per millimetre, one dot = 0.125 mm. A module must be a whole number of printer dots, or the raster driver rounds rows unevenly and the grid distorts. That quantises your choices:

Dots per module	Module size	Version 4 code (33 modules + 8 quiet)
3	0.375 mm	15.4 mm, marginal
4	0.5 mm	20.5 mm, the sweet spot
5	0.625 mm	25.6 mm, comfortable

Four dots per module at version 4 gives a 2 cm code that scans reliably at hand distance. The thermal printing page covers driver settings; the wider size logic is in size for print.

Paper width caps your version

Printable width is about 48 mm on 58 mm paper and 72 mm on 80 mm paper. At the 0.5 mm module floor, 48 mm holds 96 modules, but long before that, density defeats the thermal head's edge sharpness. Treat version 5–6 as the practical ceiling on 58 mm paper and design the payload down: a short URL, not a long one with tracking parameters bolted on. If the link will not fit cleanly, shorten it first: the capacity table shows what each version holds.

Fading is the failure mode

Direct-thermal paper has no ink; heat darkens a chemical coating, and the image keeps reacting after printing. Heat, sunlight, friction, and (notoriously) the plasticisers in PVC wallets and card sleeves all degrade it. A receipt code that scans at the till can be unreadable after a few weeks in a wallet, which matters for exactly the use cases receipts carry: warranty claims and returns.

Error correction Q buys margin against uniform fade; it cannot rescue a fully greyed-out code.
If the code must last months: warranties, asset records: print it on a separate thermal-transfer label, which uses real resin ink and does not fade.
Tell customers to scan promptly, or photograph the receipt.

What receipt codes are used for

The three payloads that earn the paper: a review request at the moment of purchase, a feedback form, and a digital copy of the receipt itself. Payment-on-receipt codes are a separate topic with their own formats: see QR codes on receipts for payment.

FAQ

What size should a QR code be on a receipt?

Two to two and a half centimetres. At 203 DPI use a whole number of dots per module, four dots (0.5 mm) per module at version 4 gives a 2 cm code. Smaller codes force fractional-dot rounding and the grid distorts.

Why does my receipt QR code stop scanning after a few weeks?

Direct-thermal paper fades. The image is a heat-darkened coating, not ink, and warmth, sunlight, friction and plastic wallets all bleach it. Print codes that must last on thermal-transfer labels instead, and use error correction Q for margin.

Can a receipt printer print a dense QR code?

Not well. A 58 mm printer has about 48 mm of printable width and limited edge sharpness, so treat version 5–6 as the ceiling. Shorten the URL rather than shrinking the modules: short payloads make low-version, big-module codes.

What error correction level should a receipt QR code use?

M if the code is scanned at the till and discarded; Q if it needs to survive in a wallet. Q keeps a code readable through roughly 25% module damage, which is meaningful against partial thermal fade.