Medicare surtax

[Locos1969]

Why am I being charged an additional 0.9% medicare tax on my return if I pay a medicare surtax on my paycheck stub?

[JohnW222]

What you see on your paycheck stub is your employer withholding the money for the 0.9% Additional Medicare Tax, as it was required to do by law. 

What you're seeing on your return is the assessment of that tax. 

That's how it works -- it's similar to the normal withholding on your Form W-2 to help offset the tax on that income reported on your return.  

Here, instead, this 0.9% withholding is designed to offset the 0.9% tax assessment on your return for Additional Medicare Tax, so as not to actually increase any tax burden come tax time.