Datetime Tools
Free online datetime tools for fast, private, browser-based workflows.
Age Calculator
Calculate your exact age in years, months, and days from your birth date. Also shows total days, weeks, and next birthday.
Open →Age Difference Calculator
Calculate the age difference between two people. Find out who is older and by how many years, months, and days.
Open →Birthday Calculator
Find out how many days until your next birthday. See your birthday on any day of the week and count down to the big day.
Open →Business Days Calculator
Calculate the number of business days (working days) between two dates. Excludes weekends automatically. Add or subtract business days from a date.
Open →Chronological Age Calculator
Calculate chronological age between any two dates in years, months, and days. Used in medical, educational, and psychological assessments.
Open →Countdown Calculator
Calculate the exact countdown to any future date or event. See days, hours, minutes, and seconds remaining. Also works for past dates.
Open →Day of the Week Calculator
Find the day of the week for any date instantly. Get the weekday name, ISO week number, day of year, and quarter for any date past or future.
Open →Day of the Year Calculator
Convert any date to its day of the year number (1–365/366), or convert a day number back to a calendar date. Works for both leap and non-leap years.
Open →EST to CST Converter
Convert EST to CST instantly. Real-time clock sync, bidirectional conversion, and automatic daylight saving time support. Free and no registration required.
Open →Half Birthday Calculator
Find your half birthday — the date exactly 6 months after your birthday. Great for kids born in summer or winter who want to celebrate at school.
Open →Hours Calculator
Add or subtract hours and minutes easily. Calculate time differences, total durations, or find a time after adding/subtracting a duration.
Open →Korean Age Calculator
Calculate your Korean age. In the Korean age system, everyone starts at age 1 at birth and gains a year every January 1st.
Open →Leap Year Calculator
Check if any year is a leap year. Find the next leap year, the previous one, and a list of upcoming leap years with dates.
Open →Military Time Converter
Convert military time (24-hour) to standard 12-hour AM/PM format and back. Includes a full military time reference chart for all hours.
Open →Overtime Pay Calculator
Calculate overtime pay based on your hourly rate and hours worked. Supports 1.5x and 2x overtime rates, with weekly total pay breakdown.
Open →Time Calculator
Add or subtract time with days, hours, minutes, and seconds. Find the result of any time arithmetic quickly.
Open →Time Duration Calculator
Calculate the exact duration between two times. Shows hours, minutes, and seconds with support for multi-day spans.
Open →Time to Decimal Calculator
Convert hours and minutes to decimal format and vice versa. Essential for timesheets, payroll, and billing calculations.
Open →Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. See UTC and local time instantly.
Open →Week Number Calculator
Find the ISO week number for any date instantly. Also shows the week start and end dates, day of the week, and how many days remain in the week.
Open →Weeks Between Dates Calculator
Calculate the exact number of weeks between any two dates. See full weeks, remaining days, total days, and working weeks. Great for planning.
Open →Work Hours Calculator
Calculate total work hours from clock-in and clock-out times. Supports lunch break deductions, multiple days, and weekly totals.
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