WordTarget is a macOS app designed to help you stick to a writing goal. It doesn't matter where or what you are writing - if your goal is to write a set amount of words a day, WordTarget will help you track yourself against that goal.
It sits unobtrusively in your menubar, and will track your word count across applications. You can start and stop it if you don't want something to count (like responding to emails or chatting on IM), and you can set it to count up to your target, or down from it, depending on what gets you more motivated!
You can also keep track of your totals for previous days with a simple view, to see how you are doing. It might encourage you to increase your goal if you're regularly exceeding it, or decrease it slightly to meet realistic expectations if you're struggling to meet your word count each day.
The app has a nicer user interface in the latest version, allowing you to directly view your previous word counts from the menu, and also now tracks per-application breakdowns of your word counts, available inline (click on a day to expand).
It also features a notification to let you know when you've hit your target, and it stores the target for each day separately now, so that amending your current target doesn't affect your success/failure (tick or cross) status for previous days.
WordTarget helps you to manage your goals, and manage your output! It's available right now on the macOS App Store for
$5.99/£5.99 $1.99/£1.99 (on sale for #NaNoWriMo for the rest of November!).
If you're having issues getting the app up and running, you can see setup instructions and a screencast for your operating system here.