Other than those things, Audio-Convert.com is similar to the other web-based converters below—add one or more files from your computer, Dropbox, or URL.
Zamzar has always been a favorite of mine. I like that it's way more than just an audio converter, but even in this context. I appreciate that it works through my browser and that I can easily import files from my favorite cloud storage services.
FileZigZag is another online option. This free audio converter service will convert the most common audio formats, so long as they don't exceed 150 MB.
Despite its name, Movavi's converter also works with audio and video files as well as images.
I like the Hamster audio converter because it installs in seconds and has a minimal, step-by-step style interface that makes it easy to use.
fre:ac is a desktop audio converter program that packs several features, making it a bit difficult to use.
Freemake Audio Converter supports several standard audio formats and is extremely easy to use.