One-handed on a phone: what we learned designing QR menus

A QR menu represents the environment where the toughest conditions for using an interface all come together: noisy, with variable lighting, possibly a weak connection, and a place where the user scrolls the page with one hand — often while holding their glass. These conditions teach, in concrete terms, what abstract UX principles actually mean in practice.

One-handed use changes everything

On interfaces designed for desktop, keeping interactive areas small rarely causes problems — the user has two hands and full control with a mouse. On a phone, though, the zone a thumb can comfortably reach is just the bottom third of the screen. An important button or filter that spills outside that zone forces the user to strain or to put the device down and hold it with both hands. In a restaurant setting, that often means giving up.

• Important action buttons should sit in the lower zone of the screen.
• Tap targets should stay large enough despite cramped menu content.
• The category tab should stay pinned — it shouldn't disappear as the user scrolls.
• Getting back to the top of the page shouldn't require a two-finger scroll.

Design for a weak connection

The network conditions at the moment a QR menu opens are unpredictable. If dozens of devices in a crowded venue are connected at once, an image-heavy page in particular struggles to load. In that case the images arrive late and the user is met with empty placeholders or shifted layouts. The structure of the menu content should be built so it stays readable even if the images don't load. The dish's price and description should be on the page independently of any image.

Speed comes before features

Every animation, filter option or visual effect added to the menu affects the page's weight and load time. The user is there to choose food — not to explore products. So design decisions in a QR menu should be judged on functional value: what does the user lose if this feature isn't there? If the answer is "not much," that feature can be sacrificed for speed.

All of these rules were tested on a single real project; on the QR ordering platform project whose details we walk through, one-handed use at the table came before every design decision.