If you want to highlight the differences between two columns of data with conditional formatting you can do so with a simple formula that uses the" not equal to" operator (e.g. ) and mixed references.
For example, if...

If you need to compare two text strings in Excel to determine if they're equal, you can use the EXACT function. For example, if you want to compare A2 with B2, use:
=EXACT(A2,B2)
If the two strings are identical,...

To verify that multiple cells have the same value with a case-sensitive formula, you can use a simple array formula based on the EXACT and AND functions. In the example shown, the formula in G5 is:
=AND(EXACT(B5:F5,B5...

To allow only values that begin with certain text, you can use data validation with a custom formula based on the EXACT and LEFT functions.
In the example shown, the data validation applied to C5:C9 is:
=EXACT(LEFT(...

Note: Excel contains many built-in rules for highlighting values with conditional formatting, including a rule to highlight cells that end with specific text. However, if you want more flexibility, you can use your own...

To confirm two ranges of the same size contain the same values, you can use a simple array formula based on the AND function. In the example shown, the formula in C9 is:
{=AND(B5:D12=F5:H12)}
Note: this is an array...

Case sensitive lookups in Excel
By default, standard lookups in Excel are not case-sensitive. Both VLOOKUP and INDEX/MATCH will simply return the first match, ignoring case.
A direct way to workaround this limitation...

To build a case-sensitive exact match, you can use the XLOOKUP function with the EXACT function. In the example shown, the formula in F5 is:
=XLOOKUP(1,--EXACT(B5:B15,"RED"),B5:D15)
which matches on "RED" (...

To count cells that contain specific text, taking into account upper and lower case, you can use a formula based on the EXACT function together with the SUMPRODUCT function. In the example shown, E5 contains this...

To perform a case sensitive match, you can use the EXACT function together with MATCH in an array formula. In the example show, the formula in E8 is:
{=MATCH(TRUE,EXACT(B5:B11,E6),0)}
Note: this is an array formula...

To match text longer than 255 characters with the MATCH function, you can use the LEFT, MID, and EXACT functions to parse and compare text, as explained below. In the example shown, the formula in G5 is:
=MATCH(1,...

Case-sensitive lookup
By default, standard lookups with VLOOKUP or INDEX + MATCH aren't case-sensitive. Both VLOOKUP and MATCH will simply return the first match, ignoring case.
However, if you need to do a case-...

Note: Excel contains many built-in "presets" for highlighting values with conditional formatting, including a preset to highlight cells that contain a specific value. However, if you want more flexibility, you can use...

To allow a user to enter only uppercase TEXT, you can use data validation with a custom formula based on the UPPER, EXACT, and AND functions.
In the example shown, the data validation applied to C5:C7 is:
=AND(EXACT...