Date Calculators
Date calculators answer questions about gaps and offsets: how many days lie between two dates, what date falls 90 days after an invoice, how old someone is on a given day, or how many working days a project has.
Each calculator states exactly how it counts. Whether the start or end date is included, how a month-end is handled and which days count as working days are visible choices, not hidden assumptions, because these details are what make two calculators disagree.
Tools in this category
Date Difference Calculate the exact difference between two dates in days, weeks, months and years. Add or Subtract Days Add or subtract days, weeks, months or years from any date. Age Calculator Find exact age in years, months and days from a date of birth. Business Days Count the working days between two dates, excluding weekends and holidays you choose. Add Business Days Find the date that falls a set number of working days from a start date. Day of the Week Find out which day of the week any date falls on. Quarter Calculator Find which calendar quarter a date is in, and when it starts and ends.
Which tool do you need?
- How long is it between two dates? Use the Date Difference calculator for days, weeks, months and years. Open the tool.
- What date is 30 days, 6 weeks or 3 months from now? Use Add or Subtract Days to move a date forward or back. Open the tool.
- How old is someone, exactly? The Age Calculator gives years, months and days and the next birthday. Open the tool.
- How many working days are there between two dates? Business Days excludes weekends and any holidays you list. Open the tool.
- What date is 10 working days away? Add Business Days skips weekends and holidays to find the date. Open the tool.
- Which weekday is a particular date? Day of the Week also shows the day number and ISO week. Open the tool.
- Which quarter is a date in? The Quarter Calculator gives the quarter and its start and end. Open the tool.
Good to know
All results are based on the Gregorian calendar and whole calendar dates. None of these tools take a time of day or a time zone into account; the Time Zone Tools do.
Calculations happen in your browser. The dates you enter are not uploaded.