Calculators and converters for front-end and everyday web work.

Font size calculator

Convert between pixels, REM, points and percent for any root font size, with a copy-ready CSS value.

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Fluid type generator

Text that scales smoothly between a small and a large screen - get a copy-ready CSS clamp() value.

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Contrast checker

Check a text and background colour against WCAG AA and AAA, and get the nearest shade that passes.

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Aspect ratio calculator

Find the ratio of any size, resize to a ratio, and build responsive image srcset markup.

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Cron explainer

Turn a cron schedule like */15 * * * * into plain English and see when it runs next.

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Timestamp converter

Convert Unix timestamps and dates between seconds, milliseconds, ISO 8601 and any time zone.

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Slug maker

Turn page titles into clean URL slugs - one per line, with accents, symbols and filler words handled.

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AI text cleaner

Strip hidden characters, curly quotes and long dashes from AI-written or pasted text - and see exactly what was removed.

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HTML shell

A clean HTML5 starter page with the head tags that matter - viewport, description, social sharing and favicons.

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