About
Redmoon Business Date Calculators is a free collection of date and business-day tools — counting working days, projecting deadlines, and applying multi-country holiday rules to the kinds of dates that decide invoices, contracts, filings, and leave. Each calculator focuses on one question and shows exactly how the result was reached.
Why we built it
Date math looks trivial until weekends, public holidays, inclusive-versus-exclusive counting, and country-specific rules collide. A deadline counted by hand is a deadline waiting to be missed. These tools carry the rules so you can rely on a single, defensible date.
How it works
- Runs in your browser. Every calculation happens client-side — your dates never leave the page.
- Multi-country holidays. Pick a country's holiday set, or add your own custom closures.
- Clear breakdowns. See the weekends, holidays, and conventions behind each answer.
- No signup, no cost. The full set of calculators is free to use.
Who makes it
It is built by Redmoon Software, which also publishes Redmoon Calculators, Redmoon Converters, and Redmoon Randomizers.
A note on accuracy
The calculators are for information only and are not legal, financial, tax, or professional advice. Holiday data and legal rule sets are simplified — always confirm a real deadline against authoritative sources. See our Terms of Use.