UI Density
Density describes how much information and how many interactive elements appear in a given area. The right density is not a universal standard — it depends on platform, user type, and session context.
Platform Defaults
| Platform | Default density | Reason |
|---|---|---|
| Desktop | Medium to high | Large screen, precise input, often primary work surface |
| Tablet | Medium | Touch input, larger than phone but less than desktop |
| Mobile | Low | Small screen, touch targets need space, interrupted sessions |
Never port a dense desktop layout directly to mobile. Remove, collapse, or deprioritise features rather than shrinking them.
User Type and Density
| User type | Appropriate density | Examples |
|---|---|---|
| Power user / enterprise | High density acceptable | Trading platforms, ERP, analytics, developer tools |
| Occasional / general user | Medium — clear visual breathing room | SaaS dashboards, project management |
| Consumer / first-time user | Low — guided, uncluttered | Onboarding flows, consumer apps, e-commerce |
A trading platform operator sits in the product for 8 hours a day and has learned every pixel — high density serves them. A user visiting a settings page once a month needs clear space and obvious labels.
Domain experts tolerate complexity — if it solves the right problem quickly. People who know the domain (especially in internal tools) will happily use dense, complex, feature-rich interfaces, because the complexity maps to a mental model they already hold. Two conditions make this work rather than overwhelm:
- Terminology matches their vocabulary. The labels, abbreviations, and jargon are the ones they already use. A term that's opaque to a consumer is a precise, fast signal to an expert — don't dumb it down for an audience that isn't there.
- The outcome stays quickly reachable. Density is fine as long as the result — the answer they came for, or the action they need — is fast to see or do, typically through an obvious primary action (see [[visual-emphasis-and-hierarchy]]). Complexity that surrounds a clear path to the outcome is power; complexity that buries the outcome is clutter.
Design a power-user mode around this: high density, expert terminology, keyboard-driven, primary action always in reach — distinct from a casual/first-time mode that guides and unclutters. The same product may offer both; match the mode to who is actually using the view.
Density Tokens
Define spacing scale with density in mind. A compact variant reduces padding without changing structure:
css/* Default density */ --density-row-height: 44px; --density-cell-padding: var(--space-3) var(--space-4); --density-gap: var(--space-4); /* Compact (enterprise / data-heavy) */ [data-density="compact"] { --density-row-height: 32px; --density-cell-padding: var(--space-2) var(--space-3); --density-gap: var(--space-2); } /* Spacious (consumer / onboarding) */ [data-density="spacious"] { --density-row-height: 56px; --density-cell-padding: var(--space-4) var(--space-6); --density-gap: var(--space-6); }
Feature Count by Platform
Not every feature belongs on every platform. For each feature ask: does a mobile user need this right now?
| Priority | Mobile | Tablet | Desktop |
|---|---|---|---|
| Core task | Always | Always | Always |
| Secondary actions | Collapsed (menu/sheet) | Visible | Visible |
| Filters and sorting | Accessible but not persistent | Collapsible | Persistent sidebar or toolbar |
| Bulk actions | Hidden or minimal | Reduced | Full |
| Advanced settings | Link to separate screen | Link or panel | Inline or panel |
| Data visualisation | Simplified (key metric only) | Reduced chart | Full chart |
Density and Feature Reduction on Mobile
Sections and features can be removed, collapsed, or repositioned on smaller viewports — not just resized.
- Remove: Decorative sidebars, secondary data columns, promotional banners
- Collapse: Filters, advanced options, secondary navigation into accordions or bottom sheets
- Reposition: Toolbars move from top to bottom (thumb reach), sidebars move to drawers
- Simplify: A multi-column data table becomes a card list; a full chart becomes a single key metric
Progressive disclosure is the principle: show the minimum needed to complete the primary task, reveal more on demand.
Reading Is Time
The most under-counted cost in a dense UI is reading. Every word the user must read to orient themselves is time spent, and it compounds — the more there is to read, the slower the whole interface feels, on every visit. Density is not just "how much fits on screen"; it's "how much the user has to read to act." Reduce that load:
- Cut words before you shrink them. The fix for a cramped screen is usually less content, not smaller type (see [[modular-scale-typography]]).
- Let recognisable icons replace reading where a concept has an unambiguous, standard icon — the eye recognises a shape faster than it reads a word (see [[brand-visual-language]]).
- But don't over-ice with icons. A wrong or decorative icon adds a thing to interpret instead of removing one; and an icon on everything is its own noise. Right icon, relevant place only.
- Front-load the scannable bit. Put the word or number the user scans for at the start of the line/label, so they don't read the whole thing to find it.
The goal: a user should be able to glance, not read, to know where they are and what to do next.
Review Checklist
- Is the density appropriate for the primary platform (desktop = can be denser, mobile = must be sparse)?
- Is the density appropriate for the user type (power user = higher density, consumer = more space)?
- Are spacing tokens used to define density — not one-off padding values?
- On mobile: are secondary features collapsed, repositioned, or removed rather than shrunk?
- Are touch targets ≥ 44×44px even in compact density variants?
- Is a density toggle offered for enterprise tools where users have strong personal preferences?
