Time & Dates Calculators
Manage deadlines, work hours, and international schedules effortlessly. Calnora’s 13 time and date tools calculate elapsed calendar and business working days, track exact chronological age down to the second, log payroll timesheet hours with break deductions, convert Unix timestamps, and coordinate multi-city meetings across global time zones.
Available calculators in Time & Dates (13)
Days Between Dates
Find exact calendar days, business working days, weeks, hours, and minutes between two dates.
Add / Subtract Days to Date
Calculate future or past target dates by adding or subtracting days, weeks, months, or business days.
Chronological Age Calculator
Determine exact age in years, months, days, total hours lived, and countdown to next birthday.
Work Hours & Timesheet
Calculate daily and weekly total working hours, lunch breaks, overtime pay, and gross earnings.
Time Zone Converter
Compare local times across international time zones (UTC, EST, PST, GMT, CET, IST, JST, etc.).
Time Duration Calculator
Hours and minutes between two clock times, minus an optional break.
Sleep Cycle Calculator
Bedtimes or wake times aligned to 90-minute sleep cycles.
Unix Timestamp Converter
Convert Unix epoch seconds to ISO dates and back.
ISO Week Number
ISO-8601 week number and weekday for any calendar date.
Day of Week from Today
Find the calendar date and weekday name after adding or subtracting N days.
Timezone Meeting Planner
Compare local business hours across multiple worldwide timezones.
Live Event Countdown
Calculate exact remaining days, hours, and minutes until any future date/time.
Julian Date Converter
Convert calendar dates and timestamps to Julian Day (JD) and Modified Julian Day (MJD).
Frequently Asked Questions — Time & Dates
How does the business day calculation work?
It iterates through the date interval, excluding Saturdays and Sundays to determine the exact count of working days for project schedules and contract milestones.
How are 90-minute sleep cycles calculated?
The Sleep Cycle Calculator works backward or forward in 90-minute REM intervals from your target bedtime or wake time, accounting for an average 15-minute falling asleep window.