Medicare coverage begins on the first day of the month you turn 65, or the first day of the month you become may be able to access through disability or end-stage renal disease

The exact date you get Medicare depends on when you were born and whether you signed up on time. If you turn 65 on any day of the month, your coverage starts on the first day of that same month. If you become may be able to access through disability or end-stage renal disease, coverage begins the first day of the month you meet the medical requirements — not the day you explore.

The lag between when you sign up and when coverage starts is separate from when coverage begins. You can sign up weeks or months before your coverage date, but the start date itself is fixed by law. If you miss the sign-up window, your coverage start date moves forward, and you may owe a penalty for the rest of your life.

Key Takeaways

  • Medicare Part A and Part B coverage starts on the first day of the month you turn 65, regardless of what day of the month your birthday falls on.
  • If you sign up during your initial enrollment period (the three months before, the month of, and three months after the month you turn 65), coverage starts the first of that birth month with no penalty.
  • If you sign up late, your Part B coverage start date moves to the first of the month after you sign up, and you pay a permanent 10 percent surcharge on your premium.
  • People who become may be able to access through disability or end-stage renal disease have coverage start on the first of the month they meet medical requirements, not when they explore.
  • You can check your coverage start date on your Social Security account or by calling Social Security at 1-800-772-1213.

How the enrollment period affects your start date

Your initial enrollment period is seven months long: it runs from three months before the month you turn 65, through the month you turn 65, and three months after. If you sign up at any point during this window, your Part A and Part B coverage starts on the first day of the month you turn 65.

If you turn 65 in June, your enrollment period runs from March through September. Whether you sign up in March or September, coverage begins June 1. The only exception is Part A: if you have worked long enough to earn it for free, Part A starts automatically on the first of your birth month whether you sign up or not. Part B requires you to sign up, and if you do not sign up during the enrollment period, your start date shifts.

If you sign up after your initial enrollment period ends, your Part B coverage does not start until the first of the month after you sign up. If you turn 65 in June and do not sign up until November, your coverage starts December 1 — a five-month gap. During those five months, you have no Part B coverage and you are responsible for all costs that Part B would have covered.

Late sign-up penalties and how they work

Signing up late for Part B carries a permanent financial consequence. You pay a late enrollment penalty equal to 10 percent of the standard Part B premium for each full 12-month period you were may be able to access but did not sign up. If the standard premium is $165 per month and you were late by two years, you pay an extra $33 per month for the rest of your life.

The penalty applies only to Part B, not Part A. Part A has no late penalty if you have worked long enough to earn it for free. If you have not worked long enough and need to buy Part A, there is a late penalty for that too, but it is less common because most people over 65 may have access to for free Part A.

The penalty does not go away if you move to a different plan or if your circumstances change. It stays on your record as long as you have Medicare. The only way to avoid it is to sign up during your initial enrollment period or to have a may have access to life event — such as losing employer coverage — that opens a special enrollment period outside the normal window.

What happens if you are still working at 65

If you are still working and covered by your employer's health plan, you may be able to delay Part B sign-up without penalty. This is called creditable coverage. Your employer plan must be based on current employment — not retiree coverage — and your employer must have at least 20 employees. If both conditions are met, you can turn down Part B and sign up later without the 10 percent penalty.

You must sign up for Part B within eight months after your employment ends or your employer coverage stops, whichever comes first. If you wait longer than eight months, the penalty kicks in. Part A, however, still starts on the first of the month you turn 65, even if you are working. You cannot delay Part A.

Tell Social Security or Medicare that you have employer coverage so they can note it in your file. When you do sign up for Part B later, bring proof of the coverage dates — your insurance card, a letter from your employer's benefits office, or a pay stub showing the deduction. This protects you from the penalty.

Coverage start dates for people on disability or with end-stage renal disease

If you become may be able to access for Medicare through Social Security Disability Insurance (SSDI), your coverage starts on the first day of the month you have been disabled for 24 months. You do not have to be 65. The 24-month waiting period is built into the law; it starts from the date Social Security determines your disability began, not from the date you applied.

If you have end-stage renal disease (ESRD) and need dialysis or a kidney transplant, you become may be able to access for Medicare when ready upon meeting the medical definition. Your coverage starts the first day of the month you meet the medical requirements. You do not have to wait 24 months. You must sign up, but there is no penalty for signing up late if you have ESRD.

In both cases, you should receive a notice from Social Security or Medicare telling you your coverage start date. If you do not receive a notice, contact Social Security at 1-800-772-1213 to confirm the date before your coverage is supposed to begin.

How to confirm your coverage start date

You can check your Medicare coverage start date through your Social Security account at ssa.gov. Sign in, go to "My Medicare", and look for your coverage information. The date will be listed as the month and year your coverage begins. If you do not have a Social Security account, you can create one on the same website.

You can also call Social Security at 1-800-772-1213 (TTY 1-800-325-0778) and ask them to confirm your coverage start date. Have your Social Security number ready. They can tell you whether you are signed up for Part A and Part B, when coverage starts, and whether you have any penalties on your record.

If your coverage start date has already passed and you have not received your Medicare card, contact Medicare directly at 1-800-MEDICARE (1-800-633-4227). They can tell you whether your coverage is active and reissue your card if it has not arrived.

What to expect in the weeks before coverage starts

About two weeks before your coverage start date, you should receive your Medicare card in the mail. The card shows your Medicare number, the type of coverage you have (Part A, Part B, or both), and the date coverage begins. Keep this card with you and show it to doctors and hospitals.

If you signed up for a Medicare Advantage plan or a prescription drug plan, your coverage for those plans also starts on the same date as Part A and Part B — the first of your birth month (or the first of the month after you sign up, if you signed up late). Your plan card will arrive separately, usually within two weeks of your coverage start date.

Before your coverage starts, review any materials Medicare sends you. They will explain what is covered, what you pay, and how to find doctors in your plan. If you have questions, call the plan directly or call Medicare at 1-800-MEDICARE.

Frequently Asked Questions

What if I turn 65 on the last day of the month?

Your coverage still starts on the first day of that same month. Medicare does not prorate coverage based on the day of the month you turn 65. Everyone who turns 65 in June gets coverage starting June 1, whether their birthday is June 1 or June 30.

Can I delay Medicare if I do not think I need it yet?

You can delay Part B if you have employer coverage based on current employment, but Part A starts automatically if you are 65 and have worked long enough to earn it. If you do not want Part B and do not have employer coverage, you can turn it down, but you will pay a penalty if you sign up later. There is no benefit to delaying if you are not working.

If I sign up in December for coverage starting in January, when does my first premium payment come out?

Your first premium is usually deducted from your Social Security check starting in the month your coverage begins. If you do not get Social Security yet, Medicare will bill you separately. The exact timing depends on your situation; Medicare will send you information about payment when you sign up.

Do I have to sign up for Part B if I already have Part A?

No, but if you do not sign up during your initial enrollment period and later change your mind, you will pay the 10 percent late penalty for as long as you have Medicare. The only exception is if you have employer coverage or a may have access to life event. If you are unsure, sign up during the enrollment period to avoid the penalty.

What if Social Security says I am disabled but I have not been disabled for 24 months yet?

Your Medicare coverage will not start until you have been on the disability rolls for 24 months. Social Security will tell you the exact date coverage begins. You can call them to confirm, but the 24-month waiting period is fixed by law and cannot be waived.