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Often in Excel you may want to calculate one of the following values:

• The due date for a task by adding a certain number of days to a start date.
• The number of days until a due date based on a start date and a due date.

Fortunately we can use simple formulas in Excel to calculate both of these values and the following examples show how to do so.

Example 1: Calculate Due Date in Excel

Suppose we have the following dataset in Excel that shows the start date of various projects and the number of days until the project is due:

To calculate the due date for each project, we can type the following formula into cell D2:

=B2+C2

We can then click and drag this formula down to each remaining cell in column D:

Column D now shows the due date for each project by adding the number of days in column C to the start date in column B.

For example:

• 1/1/2023 + 100 days = 4/11/2023
• 1/15/2023 + 30 days = 2/14/2023
• 4/12/2023 + 30 days = 5/12/2023

And so on.

Example 2: Calculate Number of Days Until Due Date in Excel

Suppose we have the following dataset in Excel that shows the start date and due date of various projects:

=C2-B2

We can then click and drag this formula down to each remaining cell in column D:

Column D now shows the number of days until each project is due by subtracting the start date from the due date.

For example:

• 1/15/2023 – 1/1/2023 = 14 days
• 2/1/2023 – 1/15/2023 = 17 days
• 4/15/2023 – 4/12/2023 = 3 days

And so on.

Note that if the number of days until the due date is a negative value (like in cell D8) then this indicates that the project is overdue.

Additional Resources

The following tutorials explain how to perform other common operations in Excel: