Calendar math, solved
Date & Time
Working days, date differences and calendar questions answered the moment you type a date — leap-year accurate.
Age Calculator
Your exact age in years, months and days — plus totals, birth weekday and a next-birthday countdown.
Date Calculator
Work out the days between two dates, add or subtract days, weeks, months and years, count down to a date, and see the weekday and week number.
Time Calculator
Add up hours and minutes, measure the time between two times including overnight shifts, total a work week with breaks and overtime, and add or subtract time from a clock.
Business Days Calculator
Count working days between two dates, with custom weekends and holiday exclusions.
Date Difference Calculator
The exact difference between two dates in days, weeks, months and years — leap-year accurate.
What this covers
Calendar and clock arithmetic: how long between two dates, what date falls a given distance away, how many working days a period contains, how old someone is, and how hours add up across a shift or a week. Dates are handled at UTC midnight, so daylight saving never moves an answer by a day.
Which tool to use
The Date Calculator is the general hub — differences, adding and subtracting, countdowns and calendar facts in one place. Use Business Days when weekends and holidays have to come out of the count, Date Difference when you only want the span between two dates, and the Age Calculator when one of those dates is a birth date and you want years, months and days plus the next birthday. The Time Calculator handles clock time rather than calendar dates: shift lengths, timesheets and overtime.
Frequently asked questions
Are leap years and February 29 handled properly?
Yes. Days are counted between UTC midnights and month lengths come from the calendar itself, so leap days are exact. A February 29 birthday is observed on March 1 in non-leap years, which the Age Calculator states on the page.
Can I use a calendar other than Gregorian?
Yes. Every date field here offers Gregorian, Jalali (Shamsi) and Hijri (Qamari), and the whole page — inputs, calendar overlay and results — follows the one you pick.
Do time zones affect the results?
Not for date arithmetic: both ends are normalised to UTC midnight first. For converting a clock time between places, use the Time Zone Converter, which resolves each zone’s offset for the specific date you enter.