Often you may want to sum the values of some dataset in Google Sheets based on week.

The following step-by-step example shows how to do so.

**Step 1: Enter the Data**

First, enter the values for a dataset that show the total sales of some product on various dates:

**Step 2: Extract the Week from Dates**

Next, we will use the **WEEKNUM** function to extract the week from each date.

In our example, we’ll type the following formula in cell **D2**:

=WEEKNUM(A2)

We’ll then drag and fill this formula down to every remaining cell in column D:

**Step 3: Find the Unique Weeks**

Next, we need to use the **UNIQUE** function to produce a list of unique weeks.

In our example, we’ll type the following formula in cell **E2**:

=UNIQUE(D2:D12)

This will produce a list of unique weeks:

**Step 4: Calculate the Sum by Week**

Next, we will use the **SUMIF(range, criterion, sum_range)** function to find the sum of the sales made during each week.

In our example, we’ll type the following formula in cell **F2**:

=SUMIF($D$2:$D$12, E2, $B$2:$B$12)

We’ll then drag and fill this formula down to the remaining cells in column F:

From the output we can see

- There were
**22**total sales made in the first week of the year. - There were
**24**total sales made in the second week of the year. - There were
**63**total sales made in the third week of the year.

And so on.

**Additional Resources**

The following tutorials explain how to perform other common tasks in Google Sheets:

How to Sum by Month in Google Sheets

How to Sum by Year in Google Sheets

How to Calculate Year to Date Values in Google Sheets