What it is for
Many deadlines are phrased as "within 30 days", "60 days from delivery", "15 working days' notice" or "in 6 months". Counting on a calendar is slow and error-prone, especially across months of different lengths or a leap year. This tool does the counting for you and shows the weekday, so you can see at once whether a deadline lands on a Saturday or Sunday.
How months and years are counted
Adding a month means moving to the same day of the following month: 15 March becomes 15 April. If that day does not exist in the target month (for example 31 January + 1 month), the result is the last available day, i.e. 28 or 29 February. The same applies to years: 29 February 2024 + 1 year = 28 February 2025.
Working days
With "working days", Saturdays and Sundays are skipped: 10 working days from a Monday lands on the Friday of the following week. Public holidays are not considered, since they vary by country.
Examples
- An invoice payable in 60 days issued on 5 September is due on 4 November.
- A 30-day notice given on 20 January runs until 19 February.
- A 2-year warranty on a purchase made on 10 June 2026 ends on 10 June 2028.
Frequently asked questions
What date is 30 days from today?
Press the "+30" shortcut with today as the start date: the result shows the date and its weekday.
What if the day doesn't exist in the target month?
The calculator uses the last day of that month: 31 January plus one month becomes 28 (or 29) February.
Can I go back in time?
Yes: choose "Subtract" to find, for example, which date it was 90 days ago.