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My Next Public Holiday

Find your next public holiday and optimise your leave for maximum time off. Supports 100+ countries with automatic location detection and a leave optimizer that maximises consecutive days off.

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My Next Public Holiday showing Anzac Day countdown for Australia

The Idea

Everyone asks the same question at some point: “When’s my next public holiday?” I wanted a fast, clean answer — with a twist. What if it could also tell you the optimal way to use your leave days for maximum consecutive time off?

Features

  • Instant next holiday with a live countdown timer
  • Leave optimizer — input your available leave days and get up to 5 ranked plans. Shows efficiency ratios like “Take 3 days off, get 9 days total at 3.0x”
  • 100+ countries with automatic location detection via browser timezone
  • Regional holiday support — state and province-level holidays (AU-QLD, US-CA, DE-BY, etc.)
  • Light and dark mode with a tropical colour palette

The Leave Optimizer

The most interesting technical challenge. The algorithm uses a greedy approach: for single-block mode, it enumerates all valid windows using exactly N leave days and picks the longest total span including adjacent weekends and holidays. For multi-block mode, it greedily selects the best block, marks those days as used, then finds the next best — generating up to 5 non-overlapping alternatives.

Technical Details

Holiday data comes from the Nager.Date API, an open-source public holidays API. The app fetches the current year plus next year to handle December-January transitions, filters by region when applicable, and caches results locally.

Location detection uses a two-tier strategy: first mapping the browser’s timezone to a country code (covers ~90 timezones), then falling back to browser geolocation with reverse geocoding for edge cases.