A client recently asked me this question: if I turned 65 in August, am I 65 on my tax return?
The answer is yes. Your age on December 31 is considered your age for the entire year.
There’s one nuance to this for people who are born on January 1st and who are turning age 65
People with birthdays on January 1st are considered to turn 65 in the prior year. Here’s what IRS Publication 17 says:
You are considered 65 on the day before your 65th birthday. For example, if your 65th birthday is on January 1, 2015, you are considered 65 for 2014.