Date and time calculators
Calculate age precisely, measure the gap between two dates, add or subtract days, count business days, convert time zones and plan countdowns.
Age Calculator
Calculate exact age in years, months and days from a birth date. Also shows total days lived, upcoming…
Date Difference Calculator
Calculate the exact number of days, weeks, months and years between any two dates. Optionally include…
Time Zone Converter
Convert a date and time between any two IANA time zones. Accounts for daylight saving transitions…
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Shows millisecond timestamps and ISO…
Date Add/Subtract Calculator
Add or subtract days, weeks, months and years from any date. Optionally count only business days…
Working Days Calculator
Count working days between two dates excluding weekends. Shows total hours and optionally accounts for…
Time Duration Calculator
Add multiple time entries to calculate total duration. Subtract breaks and apply an hourly rate for…
Sleep Calculator
Calculate the best times to wake up or go to sleep based on 90-minute sleep cycles. Avoids waking…
About Date & time tools
Dates are where software usually goes wrong: leap years, month lengths, daylight saving and week-numbering rules all bite. These tools use the IANA time-zone database and ISO-8601 week numbering, so the answers hold up when you cross a DST boundary or a year end.