Roblox UI Design Basics: Scale and Thumb Zones

Nine-slice frames, scaling rules and the thumb-zone: the UI principles that separate playable from painful.

Scale for the smallest screen

Roblox UI lives on phones, tablets, desktops and TVs. Design in Scale (percentage of screen) rather than Offset (fixed pixels) so frames resize, and test at the smallest phone viewport before shipping. Buttons need generous hitboxes — a thumb is not a mouse cursor, and the bottom corners are the natural thumb zone.

The information hierarchy

Players process a game’s UI in under a second: what is my health, what is my money, where is the button. One primary currency display, one primary action cluster, everything else in menus. Resist the urge to display every system at once — progressive disclosure (UI appearing as systems unlock) is the pattern every top game uses.

Nine-slice and style consistency

The 9-slice image property lets one bordered image scale to any button size without stretching corners — the standard for clean frames. Pick a corner radius, a border weight and two fonts, then never deviate: UI consistency reads as competence, and competence reads as trust when you ask players for a purchase.

Sources and standards

Where these figures come from

Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.

Figures, formulas and reference tables last verified: 19 September 2026.

FAQ

Scale or Offset — which should I use?

Scale for almost everything: it percentages against the parent frame so UI fits every screen. Offset is for fixed details like icon sizing inside a scaled frame.

How big should mobile buttons be?

Comfortable thumb targets run about 40-60 pixels at typical phone resolutions, with breathing room between actions. If two buttons get mis-pressed in testing, space them further.

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