About HolidayClash
HolidayClash is a free tool that helps distributed teams plan around public holidays across multiple countries.
If you've ever scheduled a global launch only to realize halfway through that half your team is on a national day off, you know the problem. Most holiday calendar sites focus on a single country at a time. HolidayClash compares them side by side, so you can see at a glance which weeks are clean, which ones are blocked, and where the long-weekend traps are hiding.
What the tool does
- Multi-country comparison. Pick any combination of 100+ countries and see all their public holidays in a single year-at-a-glance view.
- Clash detection. Days where two or more selected countries are simultaneously off get flagged automatically.
- Long-weekend spotting. Holidays that fall on a Monday, Friday, or adjacent to weekends are highlighted, since they create three- and four-day breaks that affect availability.
- Clean-week counting. A summary tells you how many ISO weeks of the year have zero holidays in any selected country — your safest windows for launches, training, and sprints.
Where the data comes from
Holiday data is sourced from Nager.Date, an open-source public holiday API maintained by a community of contributors. The data aggregates official government calendars and is updated continuously. We don't store or modify the data — we just visualize it.
What HolidayClash is not
HolidayClash is a planning tool, not a leave management or HR system. We don't track employee PTO, we don't sync with calendars, and we don't sell employee data. It's intentionally a single-purpose, free utility.
How we keep it free
The site costs almost nothing to run because it's served from a global edge network and uses an open-source data API. We may show display ads to cover costs, but core functionality will remain free without registration.
Contact
Spotted a bug, missing country, or have a suggestion? Reach out via the data source's GitHub issues for data corrections, or build feedback by replying to any email we send (if you signed up for updates).