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Font-Stack Text Coverage Checker

Compare text code points with entered coverage ranges or supported font cmaps, showing fallback and missing characters.

Files stay on your device No sign-up Free to use
How this works

The tool runs in this browser. Your file or text is not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

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or choose them from your device

Up to 4 standalone sfnt fonts, 8 MiB each. WOFF, WOFF2, collections and web URLs are refused. The stack order is the order you choose them.

    One line per stack entry as "Label | U+0041-005A, U+00A0-00FF". The label is only a name for your own list and is not checked against any real font. Up to 4 entries and 200 ranges each.

    Up to 2000 characters and 500 distinct code points.

    Declared ranges are a plan. File mode reads the real cmap tables and treats a code point that maps to glyph 0 as missing.

    How to use Font-Stack Text Coverage Checker

    1. Choose declared ranges for planning or select supported sfnt font files.
    2. Enter the exact text and order the fonts as the intended fallback stack.
    3. Review first-cover assignments, uncovered code points and unsupported cmap findings.

    Example: Font-Stack Text Coverage Checker

    Compare text code points with entered coverage ranges or supported font cmaps, showing fallback and missing characters.

    You add
    Coverage source: "declared" Declared coverage: "Entered Latin ranges | U+0020-007E, U+00A0-00FF, U+20AC\nEntered alternate ranges | U+0020-007E, U+0370-03FF, U+0400-04FF, U+1F600-1F64F" Font files: [] Text to check: "Café costs €5 - see Ω ≈ √ µ ≤ ≥ ÷ ÷"
    You get
    2 fonts checked against 20 distinct code points; 0 cover all of them, and 5 code points have no cover in the stack.

    Options

    Declared coverage
    Ranges describe your supplied plan. They are not verified coverage for a named commercial or installed font.
    File coverage
    Supported cmap records are inspected without rendering the font. Glyph zero is treated as missing under the documented mapping rules.

    Supported inputs and limits

    Up to four standalone sfnt fonts, 8 MiB each; 2,000 text characters and 500 distinct code points. Declared mode up to 200 ranges per font. Supported Unicode cmap 0/4/6/12 subset, maxp glyph bounds and a 300,000-code-point scan cap. Variation selectors/shaping controls are refused; no font rendering, license approval, WOFF/WOFF2 or shaping guarantee.

    Where your input is processed

    This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

    Mapped characters may still render poorly

    A cmap mapping does not establish shaping, readable glyph design or correct combining-mark placement. Variation selectors and complex scripts need separate rendering tests. Keep the exact text and stack order with the report before deciding that a fallback is adequate.

    Questions about Font-Stack Text Coverage Checker

    Does declared mode inspect a font?

    It checks the ranges you entered and labels them as a plan.

    Does a cmap match guarantee readability?

    No. Glyph appearance, shaping and combining behavior are not tested.

    Will font licenses be checked?

    No. Permission to use a supplied font needs separate review.

    Project manager: Tony Hines · Content updated 4 October 2026 · Report a problem

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