How is the monthly subscription charged?

If I start the subscription from 16 Dec to 15 Jan, will you charge me for one month or 2 moths?

Hi,

If you upgrade your account on December 16, 2015. You will be charge for one month and it will cover Dec 16 - Jan 15, 2016. For example, if you have upgraded your account on December 16, 2015 to Bronze Plan Monthly, on the same date you will be charge $19.00. Then your next billing date will be on January 16, 2015. On your next billing date you will be charge for another month which will cover Jan 16 - Feb 15, 2016 unless you downgrade your account to Free Plan before the next billing date. 

Do let us know if you have any further questions.
Regards.