Accurate data entry saves tonnes of time in data clean up & analysis. Below is how to Allow Only UPPERCASE, lowercase, Or Proper case Entries in Excel.
How it Works
The EXACT Function compares two text strings and returns TRUE if they are the same else FALSE. This is a case Sensitive function.
UPPER function converts all the text characters in a string to uppercase
=EXACT(D5, UPPER(D5)) Checks if the string keyed in cell D5 is the same as the its equivalent Uppercased version.
All TRUE cases are regarded as valid while the FALSE cases are rejected as Invalid