How to Add Weeks in a Date in Excel (SUPER QUICK)

One of the best features of using Excel is that it enables you to perform calculations with dates easily. For example, if you want to find a date that’s one, two, or even three weeks ahead of a given date, to set a project deadline, you can do this with a simple formula.

Since a week equals seven days, you can add 7, 14, or 21 to your original date using basic arithmetic. Excel handles the rest and returns the correct future date automatically.

Before performing this calculation, ensure that you have a valid date in Excel, formatted according to Excel’s date format. Then, you can enter a date exactly one week from the current date.

In this tutorial, we will examine each of these methods individually.

Add a Week to a Date (One Week)

Let’s say you have a date in cell A1, and you want to add a week to it in cell B1. Just enter this formula in B1:

=A1 + 7

Here, you’re simply adding 7 days (which make up a week) to the original date. Press Enter, and you’ll get the new date, exactly one week ahead.

1. First, enter “=” in cell B1.
2. Next, refer to the cell where you have the date.
3. Now, enter “+” to add.
4. In the end, enter 7 to add a single week to the date.

As you can see, after adding seven days to the data, you get 8th Dec, which is exactly one week after 1st Dec. Now, if you want to add more than one week to a date, you can multiply the 7 by that number.

In the above example, you have multiplied (7*3) to add the 21 days, which is equal to 3 weeks.

If you want to use the current date in Excel and add one or more weeks to it, you can use the TODAY or NOW function. The TODAY function returns just the current date, while the NOW function returns both the current date and the current time. To get a future date, simply add 7 for each week you want to move forward. For example, =TODAY()+7 gives you the date one week from today. If you use NOW()+14, you’ll get the exact date and time two weeks ahead of the current moment.

Add Multiple Weeks to a Date (2, 3, 5 Weeks)

Now, if you want to add more than one week to a date, you can use the same formula, but this time multiply 7 (the number of days in a week) by the number of weeks you want to add.

=start_date + (weeks_to_add * 7)
=A1 + (3 * 7)

For example, to add 3 weeks, you’d multiply 7 by 3. A better approach is to use a cell reference for the number of weeks; this way, if you change the value in that cell, the result updates automatically.

This allows you to calculate a future date that is exactly the number of weeks ahead of your original date.

Create a Custom Function to Add Weeks

You can also create a custom function to add weeks to a date using either a LAMBDA function or a VBA macro. If you prefer using the LAMBDA function, follow these steps:

First, go to the Name Manager in Excel. Click the New button to create a new named function. In the dialog box that appears, enter a name for your function, something like “AddWeeks.” Then, in the Refers to field, paste the LAMBDA formula (shared below).

Once you click OK, your custom function is ready to use. Now, back on your worksheet, you can simply type the name of your new function, and it will return a date that’s the desired number of weeks ahead of a given start date.

And in the same way, you can use the below custom function to add or remove weeks from a date.

Function AddWeeks(startDate As Date, weeks As Double) As Date
    AddWeeks = startDate + (weeks * 7)
End Function

This custom function allows you to add or subtract a specific number of weeks from a start date and takes two arguments: the start date and the number of weeks.

Too use it, first, go to the Developer tab and click on Visual Basic. Once the editor opens, go to Insert > Module, and paste the code there.

After saving, return to your worksheet, you can now use the function AddWeeks just like any built-in Excel function.

Simply enter the start date and the number of weeks you want to add (or subtract), and it will return the new date accordingly.

Add Weeks by Ignoring Weekends

Now, let’s say you want to get a date that’s a week ahead, but you don’t want to include weekends; you only want to count business days.

In that case, instead of using a basic arithmetic calculation, you can use the WORKDAY function. This function helps you skip weekends automatically, excluding non-working days.

=WORKDAY(A2, B2 * 7)
=WORKDAY(start_date, weeks_to_add * 7, holidays)

Here’s how it works: in the formula, you specify the original date, and then refer to a cell (like B2) where you enter the number of weeks you want to add.

The formula then multiplies that number by 7 to convert weeks into total days. For example, if you enter 2 in B2, it becomes 14 days. And WORKDAY will give you the date that’s 14 business days after your original date, excluding weekends.

Other Methods (SUM function)

There is one more method that you can use to add or subtract week(s) from a date. Instead of using an add or subtract operator, you can use the sum function.

In the following example, you have the sum function, where the first argument is the date and the second argument is 7, which adds 7 days to the date.

=SUM(A1,7)

And this is for multiple weeks.

=SUM(A1,7*3)

Subtract a Week from a Date

Using the same method, you can also subtract a week or multiple weeks from a date. You need to use subtraction instead of addition.

And if you want to subtract more than one week from a date, you can multiply 7 by that number.