What does this do?
Two modes: count the working days between two dates, or add (or subtract) a number of working days from a start date to find when something is due. Weekends are excluded by default; you can also paste in a list of holiday dates to skip.
What counts as a working day?
Monday through Friday, minus any dates you list as holidays. The result is inclusive of both endpoints — so a Mon → Fri week is 5 working days, not 4.
Does this handle public holidays automatically?
No — public holidays vary by country, region, and even company. Paste the
dates you want to skip into the holidays box, one per line in
yyyy-mm-dd format. Government and HR holiday calendars are
usually published as iCal or CSV; pull the dates from there.
Is anything uploaded?
No. All counting happens in your browser.