Date Calculator
Add or subtract days, weeks, months and years from any date. Calculate future dates, past dates, deadlines and business-day schedules instantly.
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How to Add or Subtract Days From a Date
Calculate a future or past date in three simple steps.
Choose a Starting Date
Select today or enter any past or future calendar date.
Enter the Time Period
Enter any combination of years, months, weeks and days to add or subtract.
Calculate the New Date
See the resulting calendar date, day of the week and calculation breakdown.
Add or Subtract Days, Weeks, Months and Years From a Date
The Fahahu Date Calculator makes it easy to calculate a date in the future or past. Choose a starting date, select whether you want to add or subtract time, and enter any combination of years, months, weeks and days.
The tool can be used for deadlines, project schedules, contract dates, travel planning, payment periods, appointments and other situations where you need to calculate a new date from a known starting point.
What Date Is 30 Days From Today?
Select Today as the starting date, choose Add Time and enter 30 in the Days field. The calculator will return the exact date and day of the week that occurs 30 calendar days later.
What Date Is 90 Days From Today?
Use the 90 Days preset to quickly calculate a date 90 days after your selected starting date. You can switch to Subtract Time if you want to find the date 90 days earlier instead.
Adding Months to a Date
Months have different lengths, so adding one month is not always the same as adding 30 days. The calculator performs calendar-month arithmetic and adjusts dates that would otherwise fall beyond the end of the target month.
For example, adding one month to a date near the end of January may result in the final valid day of February when the same day number does not exist in February.
Adding Years and Leap Years
The calculator also handles different year lengths. If a calculation begins on February 29 and the resulting year is not a leap year, the date is adjusted to the final valid day of February.
Business Day Date Calculator
Enable the business-day option when you want the days and weeks portion of the calculation to skip Saturdays and Sundays. This is useful for estimating weekday-based deadlines and working periods.
Public holidays are not automatically excluded because official holiday calendars differ between countries, regions and organizations.
Calendar Days vs. Business Days
Calendar-day calculations count every day of the week. Business-day calculations skip Saturday and Sunday when processing the days and weeks portion. Months and years remain calendar-based so the result continues to follow normal calendar arithmetic.
Related Time & Date Tools
Use Fahahu’s other free tools for date durations and worldwide time calculations.
Date Calculator FAQs
How do I add days to a date?
Choose the starting date, select Add Time, enter the number of days and select Calculate Date. The resulting date and day of the week will be displayed.
How do I subtract days from a date?
Select Subtract Time, choose the starting date and enter the number of days you want to subtract. The calculator will return the earlier date.
Can I add months and years at the same time?
Yes. You can combine years, months, weeks and days in a single calculation.
Does adding one month mean adding 30 days?
No. Months have different lengths. Adding a calendar month moves the date to the corresponding month rather than simply adding 30 days.
Can the calculator skip weekends?
Yes. Enable the business-day option and the days and weeks portion will skip Saturdays and Sundays.
Are public holidays excluded from business days?
No. Business-day calculations skip Saturday and Sunday only. Public holidays vary by location and are not automatically excluded.
Does the calculator handle leap years?
Yes. Calendar calculations account for leap years and varying month lengths.