Feather Icons and Fluent UI 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.
| Feather Icons | Fluent UI Icons | |
|---|---|---|
| Icons | 286 | 20,170 |
| Visual variants per concept | 1 — outline only | 2 — regular and filled |
| Design grid | 24×24 | 12–48 |
| License | MIT | MIT |
| Attribution required | No | No |
| Official React package | react-feather | @fluentui/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.
Landing pages, portfolios, marketing sites, and small apps where you need perhaps thirty icons and want them to look calm and deliberate. Feather is also a good teaching reference for icon grid discipline.
Consider otherwise if: For an actively maintained superset with the same aesthetic, use Lucide — it began as a Feather fork and now has 1,979 icons. Iconoir is another minimalist option with far more coverage.
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.
Feather Icons contains 286 icons and Fluent UI Icons contains 20,170. Feather Icons is the library that defined the modern minimal outline icon. Created by Cole Bemis in 2017, its 286 icons are drawn on a 24×24 grid with a 2px stroke, rounded joins, and no fill — a formula that an entire generation of icon libraries has since copied.
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.
Feather Icons is released under MIT. Commercial use, modification and redistribution with no attribution required.
Fluent UI 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 Feather Icons or Fluent UI Icons, or browse every library comparison.
Both have first-party React packages: react-feather and @fluentui/react-icons. Feather has the smaller 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.
Feather Icons has 286 icons and Fluent UI Icons has 20,170. Fluent UI Icons is larger by about 6952%. 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 — Feather uses 24×24 and Fluent UI uses 12–48 — 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.
Feather Icons is MIT: Commercial use, modification and redistribution with no attribution required. Fluent UI 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.
Feather Icons offers outline only; Fluent UI Icons offers regular and filled. 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. Feather draws on a 24×24 grid and Fluent UI on 12–48. 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.