Reference · 4 min read
Chrome Extension Icon Sizes: The Complete Guide
Which icon sizes Chrome actually needs, where each one appears, and why SVG toolbar icons silently fail.
Missing or wrongly sized icons are the most common reason an extension looks unfinished — Chrome falls back to a grey puzzle piece in the toolbar.
The four sizes and where they appear
- 16x16 — favicon-scale, used in the extension page and context menus.
- 32x32 — Windows systems and higher-DPI toolbar rendering.
- 48x48 — the chrome://extensions management page.
- 128x128 — installation dialog and the Chrome Web Store listing.
action.default_icon vs icons
The top-level "icons" object controls install and management surfaces. "action": { "default_icon": { ... } } controls the toolbar button. Declare both, pointing at the same PNG set.
Use PNG, not SVG
Chrome's toolbar does not render SVG icons. If you design in SVG, rasterise to PNG at each size before packaging — ManifestGo does this automatically for every build.
Design tips
- Keep the mark readable at 16px — one shape, high contrast, no fine text.
- Use a transparent background so the icon sits well on light and dark toolbars.
- Export at exact pixel sizes rather than letting the browser downscale 128px art.
Frequently asked questions
Are all four icon sizes required?
Technically only 128x128 is required for the Web Store, but shipping 16, 32, 48 and 128 avoids blurry rendering and the default puzzle-piece icon.