Which one is correct: “1yr” or “1yr.” or “1 yr”?

Question

I need to put one of the above on one of my app's buttons.

Bonus question - does the same rule hold in plural? That is if I write "1 yr.", do I write "15 yrs." as well?

Answer 1

As reported by the NOAD, yr. is an English abbreviation, but it could be both the abbreviation of year or years, while yrs. is the abbreviation for years. In such case, you could use 1 yr., 2 yr. and the abbreviation would always be correct.

As already reported, there should be a space between the number and yr. or year.

Answer 2

It depends a lot on context.

In geology yr is the recognised symbol for years, when talking about absolute age.

Although there has been some controversy recently. See this New Scientist article: http://www.newscientist.com/article/dn20423-push-to-define-year-sparks-time-war.html

Answer 3

As far as I know, the rules for spacing or not spacing between values and units is that there should always be a spacing between the value and the unit ("1 %" is incorrect, since percent is not a unit, but a fraction). Hence, "1yr" is incorrect, since "year" is a unit.

I'd write "1 yr", "15 yrs" if I really needed the space. In all other cases I'd prefer "1 year", "15 years", since "yr" doesn't look that good in text, in my opinion.

Answer 4

I'd say there's no correct one, but 1 yr. (or 2 yrs.) come closest, based on convention.