QR codes on event tickets

A ticket QR code must work in two forms, at least 2.5 cm when printed and about 250 px on a phone screen. Gate imagers scan fast in controlled conditions, so error correction M is enough; the real failures are screenshot fraud and low screen brightness at sunny outdoor gates.

Typical scan distance	10–25 cm (gate imager)
Minimum code width	2.5 cm print / 250 px screen
Error correction	M print / L screen

A consumer-presented code

Tickets invert the usual geometry: the attendee presents the code and a trained operator with a hardware imager — or a fixed gate scanner (a 2D imager, never a laser) — reads it at 10–25 cm. Controlled distance, purpose-built optics, motivated users. That is why the error-correction budget can be lean: M for print, and L is tolerable on screen, where there is no damage to correct and lower density means faster decodes. Dense codes are the enemy of gate throughput — a ticket ID belongs in a short token, not a 200-character URL.

Two forms, two rule sets

Print-at-home and thermal stock: at least 2.5 cm, solid black on white, quiet zone intact. Home printers running out of toner and creased A4 sheets are the print-side hazards; M-level correction covers both.

On screen: at least 250 px rendered — roughly 2 cm on a typical phone — with the brightness the decisive variable, not the pixels. Never put the code in an email image that the mail client scales down; deep-link to a full-screen pass.

The two real failure modes

Screenshot fraud. A static QR code is a bearer token: whoever shows it first gets in, and a screenshot is a perfect copy. This is the honest limit of a static ticket code, and it is why major ticketing platforms moved to rotating barcodes that refresh every few seconds and refuse screenshots. For a paid, resellable event, a static code plus a scan-once check at the gate is the minimum; UseQR generates static codes and does not provide entry management, so the duplicate-detection logic must live in your gate system.

Sunlight at outdoor gates. Phone screens washing out in direct sun is the top cause of gate queues. An imager needs on-screen contrast that a 50%-brightness screen in sunlight cannot deliver — the physics is covered in screen brightness and QR scanning. Gate staff saying "brightness up, please" is a process fix; shade structures over the scan point are a better one.

Why some tickets use Aztec instead

Airlines and railways mostly encode boarding passes as Aztec codes, not QR: Aztec requires no quiet zone, so it survives tight ticket layouts and cropped app views better. If your scanning hardware is QR-only, check the ticket template's symbology before committing — the two are not interchangeable at the gate. Wider entry-management patterns, including wristband handoff after first scan, are collected under QR codes for events.

FAQ

What size should a QR code be on a printed ticket?

At least 2.5 cm square with a full four-module quiet zone. Gate imagers read at 10–25 cm, so this is comfortably within the ten-to-one rule; going bigger buys tolerance for creased and badly printed home tickets.

How big should a ticket QR code be on a phone screen?

About 250 px rendered, shown full-screen with brightness forced high. Screen size is rarely the problem — washed-out contrast in sunlight is. A full-screen pass at maximum brightness scans in conditions where an embedded email image fails.

Can people cheat with a screenshot of a ticket QR code?

Yes. A static code is a bearer token and a screenshot is a perfect copy, so the gate system must mark each code used on first scan. Large platforms go further and rotate the barcode every few seconds to make screenshots worthless.

Why do airline boarding passes not use QR codes?

Most use Aztec codes, which need no quiet zone and pack tighter into small layouts. QR remains standard for event ticketing because phone cameras and commodity imagers all read it, but the gate hardware must match whichever symbology the tickets use.