To count the number of cells that contain negative 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...

This examples shows how to calculate a volunteer hour requirement. The requirement is to have 15 volunteer hours, with at least 5 in each category. The formula in F6 is:
=AND(COUNTIF(C6:E6,">=5")=3,SUM(C6...

To test if all values in a range are at least a certain threshold value, you can use the COUNTIF function together with the NOT function. In the example shown, the formula in G5 is:
=NOT(COUNTIF(B5:F5,"<65...

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...

Note: Excel contains many built-in "presets" for highlighting values with conditional formatting, including a preset to highlight duplicate values. However, if you want more flexibility, you can highlight duplicates...

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

To mark the first duplicate in a list, you can use a formula based on the COUNTIF function. Optionally, you can flag subsequent duplicates with a different marker. In the example shown the formula in cell C4 is:
=IF(...

To count cells that contain either one value or another, you an either use a helper column then tally up the count, or a more complex single cell formula.
Background
When you count cells with "OR" criteria, you need...

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 track student class enrollment when classes may appear in any order, you can create a table with additional columns, one for each class, to mark and count enrollment. In the example shown, the formula in G6 is:
=...

To count the number of cells equal to one of many values, you can use the COUNTIF function inside of SUMPRODUCT. In the generic form of the formula (above) rng represents a range of cells, and things represents the...

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 determine if a value exists in a range of cells, you can use a simple formula based on the COUNTIF function. In the example shown, the formula in D5 is:
=COUNTIF(rng,B5)>0
where "rng" is the named range F4:F10...

To count the number of cells that contain a certain number of characters text, you can use the COUNTIF function. In the generic form of the formula (above), rng is a range of cells, and "?" is a wildcard matching any...

To count the number of cells that 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 contain, and "*"...