$1,213.00 will be the GROSS in 2022, prior to Medicare taking its cut. Yes, I'm not taxed on SS. But the monthly Medicare premium will take me down to what figure, I'm wondering?

"In 2021, Part B increased 2.70% to $148.50 monthly from $144.60. Annually that was a $47 increase."
That is correct, but remember that the 2021 was supposed to be four times this amount or $15.60 ($3.90 x 4). It was limited to 25% by the law that was passed to help with Covid (can't remember the law's official name).
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stillers: As my wife likes to say, "Good remembering!" Here's an article about that from 09/21/20:
https://www.cnbc.com/2020/09/29/congress-may-limit-medicare-part-b-premium-increase-for-2021-.html
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It is my understanding that this will be deducted this year in addition to the new calculated amount for 2022, so whatever this year's amount calculates out to, this $11.70 ($3.90 x 3) will be added as well. Of course, this assumes that your particular SS benefit increase exceeds this Medicare increase, otherwise you are held harmless.
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stillers: Not sure how that's your "understanding " of that. I've never seen that written but I could have missed it. Do you have a reference/link? Having worked in other areas of the Program for a coupla decades, it would knock me off my chair to learn that was correct, or even contemplated as something that could pass, or pass-through, as it were. But I digress.
All that aside, and cutting to the chase, here's medicareresources.org's take on it as of 10/05/21:
https://www.medicareresources.org/faqs/how-much-does-medicare-part-b-cost/
Excerpts:
Medicare Part B costs: key takeaways
Standard Part B premiums are $148.50/month in 2021; projected to be $158.50/month in 2022...
...As described below, the Social Security cost-of-living adjustment can sometimes limit the increase in Part B premiums, but that’s not expected to be the case for 2022, as the COLA is expected to be historically large.
The Part B premium increase from 2020 to 2021 was smaller than initially projected, thanks to a short-term government spending bill that was enacted in the fall of 2020, and that included a provision to cap the increase in the Part B premium for 2021.
That ($158.50-148.50 or) $10 increase is in line with some other estimates I've seen and does not quite compute with what you posted.
And in relation to the subject of my post, a response to another poster's comment, "Medicare will eat it anyhow," even if correct, the absolute Medicare Pt B increase in 2022 will be small relative to the SS COLA increase for the vast majority of recipients.
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Just my two cents worth
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stillers: As we used to say in the bizness, "Noted."
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Volcker raised the federal funds rate, which had averaged 11.2% in 1979, to a peak of 20% in June 1981.