Calculate Business Days is a free, open-to-all utility that calculates business days accurately using real public holiday data for 166 countries. It was built to solve a common frustration: most "business days calculators" online are either too simple (they only skip weekends) or wrong (they ignore public holidays, use hardcoded calendars, or fail on countries with non-standard weekends).

How it works

The tool offers two straightforward modes. In "Add/Subtract Business Days," you enter a start date and a number of business days; the calculator returns the resulting calendar date, automatically skipping weekends and public holidays. In "Count Business Days Between Two Dates," you enter a start and end date; the calculator returns the number of working days between them, again with weekends and holidays excluded.

Real public holiday data

The calculator pulls public holiday data from the Nager.Date API, which covers 166 countries and territories. It only counts national holidays (global = true), not regional or optional ones, to keep results consistent and predictable. The data is cached in the browser for speed, with a live API fallback for future years.

Per-country weekend rules

Not every country uses Saturday–Sunday weekends. The tool handles per-country weekend configurations: the default is Saturday–Sunday, but it correctly uses Friday–Saturday for countries like Egypt, Saudi Arabia, Bahrain, Algeria, and others where applicable.

Transparent, verifiable results

Every result includes a clear breakdown: total business days, weekends skipped, holidays skipped (with names and dates), and the final date or count. Shareable result URLs let you send a calculation to a colleague - they open the link and see the same result instantly, no re-entry needed.

Embeddable widget

he tool includes a free iframe embed snippet for blogs, help centers, intranets, and client portals. The embed is responsive, lightweight, and includes a tasteful "Powered by" link back to the calculator.

Dark and light mode

The interface supports both dark and light themes, automatically matching the user's system preference or toggling manually.

Localized pages

The site includes localized homepages in 7 languages (English, Italian, Portuguese, German, Spanish, French, Japanese) It also has dedicated pages for 166 individual countries.

No signup, no limits, no ads

The tool is completely free to use. No account required, no usage caps, no advertisements, no data collection beyond anonymous analytics.

Tech stack

Built with Next.js 16, React 19, TypeScript, and Tailwind CSS. Static export deployed on Vercel. Holiday data from Nager.Date API (free, no key required). All calculations run client-side for speed and privacy.

Made by

Built by Henrik Åberg and the team behind Lapsewise (lapsewise.com), a renewal and expiry management platform for businesses.