Fluent UI Icons and Radix Icons are two of the most widely used open-source icon sets. Both are free, both ship framework packages, and both will look perfectly reasonable in a product UI — which is exactly why the choice is annoying. This page puts the two side by side using the actual artwork and the real numbers.
| Fluent UI Icons | Radix Icons | |
|---|---|---|
| Icons | 20,170 | 345 |
| Visual variants per concept | 2 — regular and filled | 1 — outline only |
| Design grid | 12–48 | 15×15 |
| License | MIT | MIT |
| Attribution required | No | No |
| Official React package | @fluentui/react-icons | @radix-ui/react-icons |
Every pair below is the same concept rendered from each library's own source files. This is the part you cannot get from a written review — the difference in stroke weight, corner rounding and optical size is the thing you will actually notice in your interface.
Enterprise applications, Microsoft 365 integrations, and products that already follow Fluent or need extremely broad coverage. The count alone means you will rarely need to look elsewhere.
Consider otherwise if: The size is also a drawback — with 20,170 icons, maintaining visual consistency across a product takes more discipline. Lucide and Heroicons are far easier to keep coherent.
Dense product UI: data tables, command palettes, context menus, settings panels, and anywhere you need an icon to occupy as little space as possible while staying legible.
Consider otherwise if: The 345-icon count is small, so you will hit gaps quickly in a large product. Heroicons also ships a drawn 16px size with many more icons; Lucide covers far more concepts at 24×24.
Fluent UI Icons contains 20,170 icons and Radix Icons contains 345. Fluent UI Icons is Microsoft's icon library for the Fluent Design System, and at 20,170 icons it is the largest set indexed on IconStash. The icons are drawn across multiple sizes from 12px to 48px and in Regular and Filled styles.
Radix Icons is a deliberately small set of 345 icons from the Radix UI team, drawn on a 15×15 grid. That grid is the whole point: Radix icons are designed to sit inside dense product interfaces — tables, toolbars, context menus, and form controls — where a 24×24 icon would force you to loosen your spacing.
Fluent UI Icons is released under MIT. Commercial use, modification and redistribution with no attribution required.
Radix Icons is released under MIT. Commercial use, modification and redistribution with no attribution required.
You do not have to commit to one. IconStash indexes both libraries, so you can search a concept once and see how each set drew it, then export SVG or PNG at any size and colour. Start with Fluent UI Icons or Radix Icons, or browse every library comparison.
Both have first-party React packages: @fluentui/react-icons and @radix-ui/react-icons. Fluent UI has the larger catalogue, so for a React app the practical difference is coverage and visual style rather than integration effort. Both tree-shake, so bundle size tracks the number of icons you import, not the size of the library.
Fluent UI Icons has 20,170 icons and Radix Icons has 345. Fluent UI Icons is larger by about 5746%. Raw count is not the whole story though — a 20,000-icon set with many near-duplicate variants can be slower to search than a tightly edited 2,000-icon set.
You can, but it usually looks wrong. Each library draws to its own grid and stroke weight — Fluent UI uses 12–48 and Radix uses 15×15 — so icons from both sit slightly differently next to each other. If you must mix them, keep each library to a distinct area of the interface rather than interleaving them in the same toolbar.
Fluent UI Icons is MIT: Commercial use, modification and redistribution with no attribution required. Radix Icons is MIT: Commercial use, modification and redistribution with no attribution required. Neither requires payment, but attribution rules differ, so check before shipping in a product where credit is inconvenient.
Fluent UI Icons offers regular and filled; Radix Icons offers outline only. If you need to express selected and unselected states with the same glyph, the library with more variants saves you from importing a second set.
At 16px, stroke weight and counter size matter more than coverage. Fluent UI draws on a 12–48 grid and Radix on 15×15. Libraries that redraw per size rather than scaling — such as Fluent UI — generally hold up best. The reliable test is to preview both at your actual render size, which you can do on any icon page on IconStash.