This website is the absolute best for equivalents and measures you need in baking. The great part is you can easily print it out and keep it in a sheet protector at the front of your recipe binder. Or bookmark it if you’re the type who has her laptop in the kitchen… Or add it to your iPhone’s home screen if you want to keep it easily accessible at all times!
I know what you’re thinking and yes, there is an app for that. It’s called Kitchen Units and while it is a good tool, I actually find the website above easier to use than the app.