Date calculations look simple until months have different lengths, leap years appear, or a deadline excludes weekends. ZaynClock's date tools are designed for these common real-life cases.
Age Calculator
An exact age is not the same as dividing a number of days by 365. The age calculator counts completed calendar years, then months, then remaining days. This is useful for birthdays, forms, school records and planning milestones.
Business Days Calculator
Business-day calculations usually exclude Sundays and may exclude Saturdays. Public holidays vary by country and region, so confirm official closure dates when a deadline has legal, payroll or travel consequences.
Date Calculator
Use the date calculator to add or subtract days, weeks, months or years. It is useful for project deadlines, return dates, appointments and subscription periods. Calendar-month arithmetic is handled with the browser's date system rather than assuming every month has 30 days.
ISO Week Number
ISO week numbering begins weeks on Monday. Week 1 is the week containing the year's first Thursday. This system is common in logistics, manufacturing, payroll and international business.
Date Countdown
A live countdown is useful for exams, birthdays, holidays, launches, trips and weddings. Keep private event details out of public share links, and verify the selected time zone when an exact launch time matters.
Unix Timestamp Converter
Unix time counts seconds since January 1, 1970 at 00:00:00 UTC. Developers use it because a single number can represent the same instant across time zones. Some systems use milliseconds instead of seconds; ZaynClock recognizes both common lengths.