Business Days Calculator

How it works

Business days are weekdays — Monday through Friday — excluding weekends and (optionally) public holidays. They are the standard unit for project scheduling, contract delivery dates, court filing deadlines, and shipping estimates. "5 business days" is conceptually simple but tedious to count manually, especially across weekends and month boundaries.

This calculator does two things. "Between two dates" mode counts how many business days fall in the range. "Add N business days" mode finds the date N business days after (or before, if N is negative) a starting date. Both modes exclude Saturdays and Sundays; we don't have a built-in holiday list because public holidays vary by country and even by US state, but the underlying function in lib/calculators/datetime.ts accepts a list of holiday ISO dates that you can wire up if needed.

Common business-day conventions to know. "Next business day" usually means the next weekday after the trigger event. "Within 30 business days" means counting forward — a 30-business-day window spans 6 calendar weeks (30 weekdays = 6 × 5). Banking and financial markets often have additional non-trading days (Federal Reserve holidays in the US, e.g., Thanksgiving, Independence Day) that aren't in our default model.

International note: Most of the world uses Monday-Friday as business days, but Israel, parts of the Middle East, and a few other regions use Sunday-Thursday. Saudi Arabia switched from Saturday-Wednesday to Sunday-Thursday in 2013. For cross-border deals, specify the calendar (e.g., "London business days") to avoid confusion.

For court deadlines, IRS filings, and other legal contexts, look up the specific jurisdiction's rules — many have additional rules about which holidays count, what happens when a deadline falls on a weekend (typically pushed to the next business day), and whether the day of the trigger event counts as day 0 or day 1.