How much of my work is protected under a copyright?

All of it that you copyright

“Copyrights protect the “original works of authorship” that are fixed in a tangible form of expression. A tangible form does not need to be directly perceptible if it can be communicated with the aid of a machine or device. For example, you need a movie projector to see a film.

Copyrightable Works Include the Following Categories

* literary works
* musical works, including any accompanying words
* dramatic works, including any accompanying music
* pantomimes and choreographic works
* pictorial, graphic, and sculptural works
* motion pictures and other audiovisual works
* sound recordings
* architectural works

These categories should be viewed broadly. For example, computer programs and most “compilations” may be registered as “literary works”; maps and architectural plans may be registered as “pictorial, graphic, and sculptural works.”

Source

Here’s a good FAQ from the U.S. Copyright Office