Date / Time Tools

Convert a date-time between multiple timezones

Calculate the duration between two dates or times

Calculate exact age in years, months, and days from a birthdate

Count business days between two dates (excluding weekends)

Find the ISO week number for any date

Add/subtract days, weeks, months, years with weekday result

Explain a cron expression in English + show the next 5 run times

Show the same instant in ISO, RFC-2822, epoch, DD/MM/YYYY and more

Build a live <div>-and-JS countdown to any ISO target timestamp

Plan a 25/5 Pomodoro session with long break — outputs a timeline

Build a standards-compliant .ics event file — import to any calendar

Parse P3Y6M4DT12H30M5S into years, months, weeks, days, time

List every date between start and end — step N days/weeks/months

Render a month-at-a-glance calendar grid — YYYY-MM input