Font Fallback Checker - Online See Missing Glyphs

A missing glyph occurs when a font does not contain a specific character. The system displays a fallback symbol — often an empty rectangle (□) colloquially called "tofu" — or uses a different font to render that character. This checker helps you identify which characters are unsupported by your chosen font.

We use HTML5 Canvas to render each character in both your target font and a reference fallback font. By comparing the pixel data, we determine if the target font renders the character with its own unique glyph (supported) or if it falls back to a system default (likely missing). A similarity threshold helps distinguish between the two cases. Note that this is a heuristic method — results are highly reliable but not 100% guaranteed for edge cases.

Most standard fonts do not include emoji glyphs. Emoji are typically rendered by a dedicated emoji font (like Apple Color Emoji, Segoe UI Emoji, or Noto Color Emoji). If your target font lacks emoji support, the system will fall back to the emoji font, and our checker will flag those characters as missing from your font — which is accurate.

You have several options: (1) Use a font with broader Unicode coverage (like Noto fonts, which aim to cover all scripts). (2) Define a proper font-family fallback stack in your CSS. (3) Use unicode-range in @font-face to specify which font covers which character ranges. (4) For web projects, consider using multiple font files with different Unicode range coverage.

Font fallback is the browser's mechanism for handling missing glyphs. When you specify font-family: "MyFont", Arial, sans-serif;, the browser tries each font in order. If a character is missing in "MyFont", it checks Arial, then the system's default sans-serif. This ensures text is always displayed, but may result in inconsistent typography. Our tool helps you identify which characters trigger fallback.

Yes! Type the Google Font name (e.g., "Roboto", "Open Sans", "Lato") into the font name field and click the "Load" button. The tool will dynamically load the font from Google Fonts and then test it. You can also upload your own custom font files (.ttf, .otf, .woff, .woff2) for testing.

The pixel-comparison method is approximately 90-95% accurate. Factors that can affect accuracy include: fonts that are very similar to the reference fallback font, subpixel rendering differences, hinting variations, and very small or very simple glyphs. Characters flagged as "uncertain" (yellow) sit in the gray zone where the tool cannot make a definitive determination. For critical projects, always verify with manual inspection.

For maximum coverage, consider: Noto fonts (Google's comprehensive family covering virtually all scripts), Arial Unicode MS, Segoe UI (good Latin/Cyrillic/Greek coverage), Helvetica World, and DejaVu fonts. For CJK: Source Han Sans / Noto Sans CJK offer extensive coverage of Chinese, Japanese, and Korean characters.