Social Security, Medicare and retirement tax, explained.

Free, plain-English guides to the decisions that shape your retirement income, built from official Social Security, Medicare and IRS sources.

• When to claim Social SecurityHow full retirement age, early claiming and delayed credits change your benefit.
• Is Social Security taxable?How much of your benefit can be taxed, and what raises or lowers it.
• Medicare IRMAA surchargesHow your income can raise your Medicare premiums, and what you can do about it.