To count unique numeric values in a range, you can use a formula based on the FREQUENCY and SUM functions.
For example, assume you have a list of employee numbers together with hours worked on "Project X", and you want...

To display a check mark if the value passes some kind of test, you can use a formula based on the IF function together a symbolic font like Wingdings.
In the example show, the formula in C5 is:
=IF(COUNTIF(allowed,B5...

To extract only unique values from a list or column, you can use an array formula based on INDEX, MATCH, and COUNTIF.
In the example shown, the formula in D5 is:
{=INDEX(list,MATCH(0,COUNTIF($D$4:D4,list),0))}
where...

Note: Excel has a built-in data validation rules for dropdown lists. This page explains how to create a custom validation rule when you want to *prevent* a user from entering a value in a list.
To allow only values...

To count the number of cells that contain values not equal to a particular value, you can use the COUNTIF function. In the generic form of the formula (above) rng represents a range of cells, and X represents the value...

If you need to determine if a range or column contains specific text (a specific substring or partial text), you can use a formula based on the COUNTIF function with wildcards.
In the example shown, the formula in D5...

To count the number of cells that contain text (i.e. not numbers, not errors, not blank), use the COUNTIF function and a wildcard. In the generic form of the formula (above), rng is a range of cells, and "*" is a...

When working with data, a common need is to perform summary calculations that show total counts in different ways. For example, total counts by category, color, size, status, etc. The COUNTIF function is a good way to...

Preface
This is an annoyingly long introduction, but the context is important, sorry!
If you try to count very long numbers (16+ digits) in a range with COUNTIF, you may see incorrect results, due to a bug in how...

To count the number of cells that have values greater than a particular number, you can use the COUNTIF function. In the generic form of the formula rng represents a range of cells that contain numbers, and X represents...

If you want to compare two ranges, and count total matches between the two ranges, you can use a formula that combines the COUNTIF and SUMPRODUCT functions.
Context
Suppose you have a "master" list of some kind, and...

To count positive numbers in a range of cells, you can use the COUNTIF function. In the generic form of the formula (above) rng represents a range of cells that contain numbers.
In the example, the active cell contains...

Note: Excel has a built-in data validation rules for dropdown lists. This page explains how to create a your own validation rule for lists when you don't want the dropdown behavior.
To allow only values from a list in...

To count the number of cells that do not contain certain text, you can use the COUNTIF function. In the generic form of the formula (above), rng is a range of cells, txt represents the text that cells should not contain...

To search multiple worksheets in a workbook for a value and return a count, you can use a formula based on the COUNTIF and INDIRECT functions. With some setup, you use this approach to search an entire workbook for a...