Free online date, age, and time calculators. Pick a calculator below, enter your dates, and get an instant answer in your browser. Nothing you type is stored or sent to a server.
Age and birthday calculators
- Age Calculator – exact age in years, months, and days
- Birthday Calculator – weekday you were born and your next birthday
- Half Birthday Calculator – the date six months after your birthday
- Anniversary Calculator – days together and the next milestone day
Date calculators
- Date Difference Calculator – days, weeks, and months between two dates
- Add or Subtract Days Calculator – a date days before or after any date
- D-Day Calculator – countdown to a future date or days since a past date
- Day of Week Calculator – weekday, day of year, and week number for any date
- Weeks Between Dates Calculator – full weeks and extra days between dates
- Months Between Dates Calculator – whole months and extra days between dates
Time and work calculators
- Business Days Calculator – working days between two dates
- Time Difference Calculator – hours and minutes between two times
How these calculators work
Every calculator on this site runs entirely in your browser. Enter a date or time, press the calculate button, and the result appears instantly with a plain-English explanation, an example, and answers to common questions on the same page.