Equals is an app for calculating almost anywhere you can edit text on OS X. It lives in your menu bar and offers “services” to other Mac apps. These services let you borrow features from other programs.
You can use them via the “Services” submenu of the app menu in other apps; the one with the app’s name in bold type in the upper left-hand corner of your screen. Additionally, there are convenient keyboard shortcuts.
The full version is available on Apple’s Mac App Store.
For more details, please check equals.geheimwerk.de.