Tension Software (www.tensionsoftware.com) has updated Menu Calendar for OS X to version 1.1. The app makes available under the menu bar, in any Mac app you’re running, a small calendar.
Clicking Menu Calendar’s icon not only shows a small standard calendar that you can use to navigate inside any month, it also makes available a small area under the calendar for date calculation. You can add (or subtract) days, months, years and the tool will instantly show the resulting day. You can also optionally select from the menu to have it launch when you log in.
Menu Calendar 1.1 provides two different date result formats (small and medium). It also includes a PDF user guide.
Menu Calendar works with OS X Yosemite or El Capitan. It costs $1.99.