Use this days calculator to add or subtract calendar days from any start date. Enter the date, number of days, and operation to find the exact result date, weekday, weeks breakdown, and quick offset dates for common planning windows.
Enter a start date and number of days to add or subtract, then see the result date and weekday.
Privacy note: calculator inputs stay in your browser and are not sent to an Age Finder server.
A days calculator adds or subtracts a selected number of calendar days from a start date. It helps answer questions like what date is in 30 days, what date was 90 days ago, or which weekday falls after a deadline window. This tool includes weekends and holidays because it counts calendar days, not business days. The result shows the final date, weekday, days moved, weeks breakdown, and quick offsets such as 7, 14, 30, 60, 90, 100, 180, and 365 days.
If the start date is January 1, 2026 and you add 30 days, the result date is January 31, 2026.
Use the subtract option for past dates such as 7 days ago, 30 days ago, or 90 days ago.
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Choose the start date, enter the number of days, select Add days, and click Calculate days. The result shows the final date and weekday.
Choose the start date, enter the number of days, select Subtract days, and calculate. The result shows the date that many calendar days before the start date.
Use today's date as the start date, enter 30, select Add days, and the calculator will show the date and weekday 30 calendar days from today.
Use today's date as the start date, enter 90, select Subtract days, and the result will show the date 90 calendar days ago.
Yes. It counts calendar days, so weekends are included. For business-day counting, use a date difference tool that supports business days.
Yes. Holidays are included because this is a calendar-day calculator. It does not remove public holidays or workdays.
Yes. Select Subtract days and enter the deadline date as the start date to find a reminder date or preparation date.
Yes. Select Add days and enter the event date as the start date to find follow-up dates, review dates, or future checkpoints.
The weeks breakdown converts the number of days into full weeks plus remaining days, such as 30 days becoming 4 weeks and 2 days.
Yes. After calculating, you can save the result as PDF, Word, or TXT, or share the result text when your browser supports sharing.