Is it worth it to use Webpack for small projects?

I know the basics of webpack, I haven’t used it in a big project though. I know that bundling js files with it makes the bundle huge, but with optimization it can be easily reduced.

But how much? Where’s the limit line for reduction the size?

Size
I assume that if my project’s size is 100kb, after including webpack it won’t be near that size, but much bigger, after minimizing and adding plugins.

Loading time
I assume that there is advantage in one server request for downloading the bundle over requesting js files separately. But how can you measure that when loading one bigger file would be more profitable than loading several smaller files separately. Is there a way for roughly estimation of that? Or do I have to switch for webpack with the whole project and check it manually with dev tools. Maybe there’s a tool? Or you count it somehow?

I know webpack makes it easy with handling multiple assets and modules, or splitting vendor dependencies, but I think sometimes it’s not worth it. How do you approach the situation when you say “aha! yes, i see webpack will do to speed up my app”?