Add Days to Date Calculator

Add or subtract days, weeks, months or years from a date, with an option to count only business days. Example: 90 days after November 11, 2026 is February 9, 2027.

How to use the Add Days to Date Calculator

1. Pick the start date.
2. Enter the amount, choose the unit and whether to add or subtract.
3. Press Calculate to see the resulting date and weekday.

Formula and method

Days and weeks are added to the calendar date. Months and years keep the day of the month, clamped to the last day of a shorter month. Business days move forward one weekday at a time, skipping Saturdays and Sundays.

Worked example: 90 days from November 11, 2026

Common deadlines from November 11, 2026

Uses

Use it for contract terms, return windows, project deadlines, loan due dates, due dates for pregnancy milestones and notice periods.

Frequently asked questions

How do I add days to a date?

Pick the start date, enter the number of days and press Calculate.

Can I subtract days?

Yes, choose Subtract.

How are months added?

The day stays the same, or moves to the last day of a shorter month.

What are business days?

Monday to Friday. Holidays are not removed.

What date is 90 days from today?

Set the start date to today and add 90 days.

Does it handle leap years?

Yes.

Sources

• Time and Date: Date calculator
• NIST: Time

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