Material Design Icons vs Phosphor
MDI is a large filled Material-style library. Phosphor is a weighted family from thin to duotone.
- MDI is the one to search when the metaphor is obscure and you need any reasonable glyph.
- Phosphor is the one to search when the same icon must exist in several weights.
- MDI is Apache 2.0. Phosphor is MIT. Both allow use in products. Keep the license notice.
Which one to open
Open Material Design Icons when the metaphor is obscure and you need any reasonable filled glyph: hardware, maps, medical, and the long tail of app actions. Open Phosphor when the same metaphor must exist in more than one weight and the design system already names that ramp.
Phosphor is the wrong search for a single filled Material-style glyph. MDI is the wrong search when the product must stay on one stroke weight. Coverage favors MDI; weight consistency favors Phosphor. The cards above open each collection.
Fill versus a weight ramp
MDI is a large filled library in a Material-like drawing. It is not the official Material Symbols font. Phosphor names end in the weight: thin, light, regular, bold, fill, or duotone. Pick one weight for a product. Fill and duotone are not interchangeable with a thin stroke.
Do not drop one MDI icon into a Phosphor toolbar. The fill and the corner will jump. The samples below are names that exist in both sets, so you can see the drawing before you choose a dependency.
When to pick MDI vs Phosphor
Pick MDI when search coverage matters more than a single thin stroke, including domain icons smaller outline sets miss. Pick Phosphor when the UI already ships a weight scale and every toolbar icon must exist at those steps.
License
MDI is Apache 2.0. Phosphor is MIT. Both allow use in a product if you keep the notice. Brand-like symbols in MDI are still artwork under Apache 2.0, and a trademark can limit how you use a logo. See Licenses. Follow the upstream license. This site is not legal advice.