Date & Time

Calculate age in total days from days lived input (use the date-based age calculator for calendar dates).

Count the total days, weeks, and business days between two dates instantly.

Count weekdays between dates, with optional weekend exclusion.

Add or subtract days, weeks, months, or years from a date.

Calculate age in years, months, and days.

Calculate someone's age on a specific past or future date.

Convert a date and time between IANA time zones.

Compare working-hour overlap across multiple time zones.

See current times in popular cities and time zones.

Create a local countdown to a date and time.

Run a clean browser stopwatch with lap times.

Run a local Pomodoro timer for focused work sessions.

Find the ISO 8601 week number for any date, using Monday as the start of the week.

Calculate invoice due dates from issue date and net terms.

Estimate pay period ranges from a start date and cadence.

Look up public holidays by country and year using the free Nager.Date API.

Estimate whole and decimal months between two dates.

Calculate days, hours, and minutes until a future date.

Calculate deadline dates from a start date and duration.

Show current Unix time in seconds and milliseconds.

Estimate due date from last menstrual period date.

Estimate an ovulation window from cycle dates.

Search common time-zone abbreviations and offsets.

Find the ordinal day number for any date.

Find the calendar quarter (Q1-Q4) and month number for any date.

Find the next weekday after a selected date.

Estimate work hours between dates from weekdays and hours per day.

Calculate days until the next birthday from a birth date.

Find fiscal quarter from a date and fiscal year start month.

Calculate elapsed hours between two times entered as 24-hour clock values.

Calculate paid shift hours after subtracting an unpaid break.

Add daily work hours into a weekly total and estimate overtime hours.

Convert decimal hours into whole hours and minutes.

Round worked minutes to a chosen payroll rounding interval.

Find overlapping working hours between two daily availability windows.

Estimate shift end time in minutes after midnight from start time, shift length, and breaks.

Calculate billable hours after non-billable time and utilization percentage.