Mr or Mr. ?

Getting buggy responses about this on my Word program, it keeps telling me to add a period to Mr.

Anyone got a firm answer on this? Or is it a 'do whatever' answer?

 

Since it is an abbreviation of "Mister" I'd say you should go with the period, at least that's how we'd do it in Sweden (or rather, how it should be done in Sweden, though no one really cares).

 

Yes, the period should be there.

 

Technically the period belongs but it's pretty common to see it left off.

 

Like in most other abbreviations/acronyms (what's the difference between those two, btw?) it seems... The question is if people do if because they are lazy or if it just falls away in the heat of writing.

 

"Mr." is generally used in America (I've heard), and it's correct to only use "Mr" in the UK.

 

actually, in a practical/logical sense, the period doesn't belong, because there are no letters elided after the final 'r' as happens to all the letters after the 'o' in 'co.' or after the 'p' in 'corp.'... ditto for 'inc.' and all other abbreviations [including 'abbrev.'] that lose their last letters... but the custom has been to add the period to 'Mr.' or 'Mrs.', so it should still be there, till custom changes widely enough to make it the norm...