Yes,
you have one year (365 days) from the purchase date; however, you may purchase an
extension of time (within 60 days of the expiration). To purchase an extension,
you can log in to your account and click 'Extend Expiration.'
You
will see the expiration date of your exam within your account under 'Take Exam'
or under the 'Extend Expiration' date.

1 year (365 days)