The answer is dependent on field type. See character limits by field type below.
- Standard text fields can hold up to 50 characters (with some exceptions, for example, phone numbers are limited to 15).
- Text 1- Text 11 can hold up to 200 characters.
- Comment fields can hold up to 1000 characters.
- Unicode fields can hold up to 4000 characters.
- Long text fields can hold up to 120,022+ (possibly an unlimited number) of characters. There are only 2 long text fields available in the standard contact fields table (Additional_ and Comment_).
Some field types (like Number fields) are restrictive about the format of the data stored there (number fields need to be whole numbers, not decimals).