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Font Size Pro Pro
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Test Font Sizes Before You Ship
Paste any text, adjust size, spacing and contrast live, and see exactly how readable it is.
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Paste or type up to 20,000 characters of text to preview
Font size slider 10–72 px, line height 1.0–2.5, letter spacing -1 to 5 px
4 built-in presets: Compact, Comfortable, Large, Extra Large
Text and background color pickers with live WCAG contrast ratio and AA/AAA pass/fail
Copy generated CSS (font-size, line-height, letter-spacing, color, background) to clipboard
Settings remembered in localStorage
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Save unlimited custom presets (free: none saved, built-ins only)
Read-aloud using browser speech synthesis with speed 0.5–2x and voice choice (free: locked)
Compare mode: 3 side-by-side sizes at once (free: single preview)
Export settings and presets as CSV, JSON, or PDF (print dialog)
Text limit raised to 200,000 characters
Font family choice: 8 system font stacks (free: default sans-serif)
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