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:

To calculate the number of days until each project is due, we can type the following formula into cell **D2**:

=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:

Excel: Apply Conditional Formatting to Overdue Dates

Excel: Apply Conditional Formatting to Dates Older Than 1 Year

Excel: How to Add Working Days to a Date