In this section, I will introduce some formulas to count birthdays by a certain month, year, or date range in Excel.

Countif by a certain month

Supposing you are going to count birthdays which are in a specific month of 8, you can enter below formula into a blank cell, and then press the Enter key.

=SUMPRODUCT(1*(MONTH(C3:C16)=G2))

Countif by a certain year

If you need to count the birthdays by a certain year, says 1988, you can use one of below formulas as you need.

Note: The second formula an array formula. Please remember to press the Ctrl + Shift + Enter keys together after entering the formulas;

Countif by a certain date

If you need to count by a specific date (says 1992-8-16), please apply below formula, and press the Enter key.

=COUNTIF(B2:B15,"1992-8-16")

Countif by a certain date range

If you need to count if later/earlier than a specific date (says 1990-1-1), you can apply the below formulas:

To count if between two specific dates (says between 1988-1-1 and 1998-1-1), please apply below formula:

=COUNTIFS(B2:B15,">"&"1988-1-1",B2:B15,"<"&"1998-1-1")

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Easily count by Fiscal year, half year, week number, or day of week in Excel

The PivotTable Special Time Grouping feature, provided by Kutools for Excel, is able to add a helper column to calculate the fiscal year, half year, week number, or day of week based on the specified date column, and let you easily count, sum, or average columns based on the calculated results in a new Pivot Table.

If you have Kutools for Excel installed, you can apply its Select Specific Cells utility to count the number of occurrences by specified date, year, or date range in Excel easily.

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1. Select the birthday column you will count in, and click Kutools > Select > Select Specific Cells. See screenshot:

2. In the opening Select Specific Cells dialog box, please do as above screenshot shown:
(1) In the Selection type section, please check one option as you need. In our case, we check the Cell option;
(2) In the Specific type section, select the Greater than or equal to from the first drop down list, and then type the first date of the specified date range in right box; next select the Less than or equal to from the second drop down list, and type the last date of the specified date range in right box, and then check And option;
(3) Click the Ok button.

3. Now a dialog box pops out and shows how many rows have been selected as below screenshot shown. Please click the OK button to close this dialog box.

Notes:
(1) For counting the number of occurrences by specified year, just specified the date range from the first date of this year to the last date of this year, such as from 1/1/1990 to 12/31/1990.
(2) For counting the number of occurrences by specified date, such as 9/14/1985, just specify the settings in the Select Specific Cells dialog box as below screenshot shown: