Add Calendar Days to a Date

Description

This calculator adds calendar days to a date using the DATE + DAYS formula. You enter a start date and the number of days, and the tool calculates the resulting date, accounting for all calendar days (including weekends and public holidays).

The tool is designed for practical personal and business tasks: calculating delivery times, planning holidays, determining project completion dates, tracking warranty periods, and any other situation where you need to work with calendar days.

"Include Start Date" Setting

This setting determines whether the start date itself is counted as the first day of the period being added. The final result directly depends on this setting.

If the checkbox is checked – the start date is included in the count (since the first day is already accounted for).
For example: 5 May + 1 day = 5 May. This is useful when you need to calculate a period "from today inclusive".

If the checkbox is unchecked – counting starts from the next day.
Same example: 5 May + 1 day = 6 May. This mode corresponds to the standard calendar count "in N days".

The choice of mode depends on the context of your task. Including the start date is often required when calculating periods where the starting day is already part of the term (for example, the first day of leave, sick leave, or a business trip).

Calculation Examples

The same example is highlighted in bold with different setting states to demonstrate its effect.