Guides
The questions that come before the tool — what a limit means, what a format contains, what counts. Each one ends at the tool that does the job.
RRULE in plain Englishrrule→datesWhat every part of an iCalendar RRULE means — FREQ, INTERVAL, BYDAY, BYMONTHDAY, BYSETPOS, COUNT and UNTIL — with worked examples, and the dates a rule silently skips.Business days, working days and calendar daysdate→workdaysWhether Saturday is a business day, whether "2 business days" includes today, and how business, working and calendar days differ — with the counting rules deadlines actually use.KB, MB and GB: what “must be under 100 KB” meansbytes→kbWhat an upload limit like "less than 100 KB" or "max 2 MB" actually means, how KB, MB and GB relate, why 1,000 and 1,024 both appear, and how to get a photo or PDF under the limit.How to create an .ics file, and what is inside oneevent→icsFour ways to make an iCalendar (.ics) file — writing one by hand, exporting from Outlook, Google Calendar or Apple Calendar, or generating one — and the parts of the format that trip people up.