Fibonacci ToolBox

Time zone converter

Convert a meeting time between zones, with working-hours flags. Knows every IANA zone and DST rule.

Time zone converter options
Runs in the background · stops after 60s
Results appear hereFill in the form and press Run.
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Cron explainer

Explain a cron expression in plain English and list its next run times in any time zone.

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Unix timestamp converter

Convert Unix timestamps (s, ms, µs, ns) to dates and back, across time zones and formats.

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SQL / XML / HTML / CSS formatter

Beautify or minify SQL, XML, HTML and CSS.

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Colour converter & contrast

Convert between HEX, RGB, HSL and OKLCH, build tints and shades, and check WCAG contrast.

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