First Time Medicare
Operated by HealthBenefitsCompass LLC, a subsidiary of HealthcareGPS Inc.Medicare education · Not a government websiteReviewed by Lauri Middleton, RN, MSN (licensed Medicare agent) and Karen OrillaHow we prepare our guidance →Meet our reviewers →

Reviewed for accuracy by Lauri Middleton, RN, MSN, licensed Medicare agentReviewed for clarity by Karen OrillaMeet our reviewers →

Decision 1 of 5

Enroll now, or delay?

Do I sign up for Part B in my first window, or wait because I have coverage from work?

What this is

Part A is usually free and most people take it at 65. Part B has a monthly premium, and the question is timing: take it in the first window, or delay it because a current job (yours or a spouse's) already covers you.

Delaying is only safe when the coverage comes from current employment. COBRA, retiree plans and the individual market do not protect you from the late-enrollment count.

Part BMedical insurance: doctor visits, outpatient care, tests, preventive services and equipment. It has a monthly premium, and this is the part the enrollment windows and penalties are mostly about. Glossary →
Initial Enrollment PeriodYour first, seven-month window around the month you turn 65. Glossary →
Special Enrollment PeriodA window that opens because of a life event — most commonly, leaving coverage from a current job. Glossary →
Who pays firstWhen you have Medicare and another plan, one of them pays first and the other second. With a current job at an employer of 20 or more, the job plan pays first; under 20, Medicare pays first. Glossary →
COBRAContinuing a job plan for a while after leaving the job, at your own cost. It is not coverage from a current job, so it does not delay the Part B clock. Glossary →
Applied to your calendar

Draw a calendar first and this section will use the actual dates.

Start my calendar

What changes if you wait
  • Waiting without current-job coverage adds 10 % to the Part B premium for every full 12 months, for as long as Part B lasts.
  • Signing up late also delays when coverage starts — there is no backdating for Part B.
  • Taking Part B while still contributing to an HSA has tax consequences; the HSA question on the calendar covers it.
Ask a real person
Ask the benefits office at work:
Ask Social Security (1-800-772-1213):
Where things stand
Next decision →

The rules we use

The first enrollment window is seven months long

It starts three months before the month you turn 65, includes that month, and ends three months after it. If your birthday is on the 1st, the whole window moves one month earlier.

Source: Medicare.gov — When does Medicare coverage start? · In effect since 2023-01-01 · Last checked 2026-09-06

When coverage starts depends on when you sign up

Sign up in the three months before your birthday month and Part B starts on the first day of that month. Sign up in your birthday month or the three months after, and it starts on the first day of the month after you sign up. The older two-to-three-month delays ended in 2023.

Source: Medicare.gov — When does Medicare coverage start? · In effect since 2023-01-01 · Last checked 2026-09-06

Leaving job coverage opens an eight-month window

If you or your spouse are still working and you have health coverage from that job, you can sign up for Part B later without a penalty. The window is eight months, starting the month after the job or the coverage ends — whichever comes first. COBRA and retiree coverage do not count as coverage from a current job.

Source: Medicare.gov — Working past 65 · In effect since 2023-01-01 · Last checked 2026-09-06

Employer size decides who pays first

With 20 or more employees, the job plan pays first and Medicare second, so delaying Part B is usually safe while that coverage lasts. With fewer than 20, Medicare pays first — and if you have not signed up, the job plan may pay very little.

Source: Medicare.gov — Working past 65 · In effect since 1986-01-01 · Last checked 2026-09-06

Part B late enrollment: 10 % for each full year late

For every full 12-month period you could have had Part B but did not — and were not covered by a current job — the monthly premium goes up by 10 %. It stays that way for as long as you have Part B.

Source: Medicare.gov — Avoid late enrollment penalties · In effect since 1966-01-01 · Last checked 2026-09-06