Do you or your spouse (or former spouse) have at least 40 calendar quarters (10 years) of work in any job at which you paid Social Security taxes in the U.S.; or are you eligible for Railroad Retirement benefits; or were you a federal employee after December 31, 1982 or a state or local employee after March 31, 1986?

If yes:
You are eligible for premium-free Part A based on your work history or federal employment. You may be eligible for premium-free Part A based on your spouse’s work history if you meet certain criteria.

If no:
You may have to pay the Part A premium. Your monthly Part A premium will depend on how many years you or your spouse worked in any job at which you paid Social Security taxes in the U.S.

In 2018 your monthly Part A premium will be
$0 If you or your spouse worked for 10 years or more or you were a federal employee on January 1, 1983
$232 If you or your spouse worked between 7.5 and 10 years
$422 If you or your spouse worked fewer than 7.5 years

 
If your income is low, you may be eligible for the Qualified Medicare Beneficiary (QMB) program, which pays for your Medicare Part A and B premiums.