The start/end days of the ATP tournaments weren't published yet, so I'm basing this version on the 2015 calendar - info about Sunday starts and Saturday finals might still change.
The calendar you see below has all the ATP and WTA tournaments for 2016, including information about tournament category (250/500/M1000/GS for the men, International/Premier/P5/PM/GS for the women), surface, and dates (including Sunday starts or Saturday finals).
If you're using Google Calendar, you can add these calendars (ATP and WTA separately, for those who only want one of them) to your schedule with a couple of clicks (in fact, if you've already added a previous version to your Google Calendar, the 2016 events are already there!).
If you're using a different calendar, you can import the calendars separately in iCal format for the ATP, and the same for WTA (iCal). Or, you can just use the calendar in this post, if you wish!
If, for some reason, you want to get only the 2016 events (the current calendars include all events from 2013 to this day), you can download the 2016-only calendars from here.