Get person's age in Ruby

Question

I\'d like to get a person\'s age from its birthday. now - birthday / 365 doesn\'t work, because some years have 366 days. I came up with the following code:

Answer 1

To account for leap years (and assuming activesupport presence):

def age
  return unless birthday
  now = Time.now.utc.to_date
  years = now.year - birthday.year
  years - (birthday.years_since(years) > now ? 1 : 0)
end

years_since will correctly modify the date to take into account non-leap years (when birthday is 02-29).