The simplest strategy for deciding whether a word that is followed by a period is an abbreviation or a regular word is to apply well-known heuristics based on the observation that single-word abbreviations are short and normally do not include vowels (Mr., Dr., kg.).
a word without vowels can be guessed to be an abbreviation unless it is written in all capital letters and can stand for an acronym or a proper name (e.g., BBC).