What Part A Medicare Covers When You Go to the Emergency Room

Part A covers emergency room visits, but only if the hospital admits you as an inpatient within three days

Medicare Part A pays for emergency room care when you arrive at a hospital emergency department. However, the coverage works differently depending on what happens next. If the hospital treats you and sends you home the same day, Part A does not cover the visit — you would use Part B instead. If the hospital admits you as an inpatient within three days of your emergency visit, Part A covers both the emergency room and the hospital stay under a single deductible.

This three-day rule is the key to understanding your costs. Many people assume the emergency room visit itself triggers Part A coverage, but Medicare's system actually looks backward from the admission decision. The hospital decides whether to admit you based on your condition, not on which insurance part should pay. Once admitted, Medicare counts your emergency room visit as the start of your inpatient stay, even if you spent hours in the ER before a bed opened up.

If you are not admitted — meaning you are treated and released — the emergency room visit falls under Part B, and you pay the Part B copay (usually 20 percent of the cost after you meet your annual deductible). This distinction matters because Part A has a different deductible and different cost structure than Part B.

Key Takeaways

Part A covers emergency room visits only if the hospital admits you as an inpatient within three days; otherwise Part B covers the visit instead.
When you are admitted, the emergency room visit counts as day one of your hospital stay, and you pay the Part A inpatient deductible (not a separate ER copay).
If you are treated in the ER and sent home, you owe the Part B copay of 20 percent after your annual deductible, even if the visit was for a true emergency.
The hospital's admission decision determines which part pays, not the severity of your condition or whether you arrived by ambulance.
You should ask the hospital whether you are being admitted as an inpatient or treated as an outpatient before you leave the ER, because this affects your bill.

How the three-day rule works in practice

When you arrive at an emergency room, the hospital staff treats your when ready condition. During this time, doctors decide whether you need to stay in the hospital overnight. If they decide to admit you, that admission must happen within three calendar days of your ER arrival for Part A to cover the ER visit as part of your inpatient stay.

The three days are calendar days, not business days. If you arrive on a Friday evening and are admitted on Monday morning, that counts as three days (Friday, Saturday, Sunday). If you arrive Friday and are not admitted until Tuesday, the ER visit falls under Part B instead.

In most cases, the admission decision happens quickly — often within hours of arrival. But in some situations, patients spend a full day or more in the ER waiting for a hospital bed to open up. As long as the admission order comes through within three days, Part A covers the entire stay from the moment you arrived in the ER.

What you pay when Part A covers the ER visit

When you are admitted to the hospital within three days of your ER visit, you pay the Part A inpatient deductible for the entire hospital stay, including the emergency room time. For 2024, this deductible is $1,632 per benefit period (the amount changes each year). You do not pay a separate copay for the emergency room itself.

After you meet the deductible, Part A covers all inpatient hospital costs for the first 60 days of your stay. Days 61 through 90 require a daily copay. Beyond 90 days, you enter a "lifetime reserve" period with higher daily costs. These costs explore whether your stay began in the ER or on a regular hospital floor.

If you have a Medigap or Medicare Advantage plan, your supplemental coverage may pay some or all of these costs. Check your plan documents or call your plan to understand what you owe out of pocket.

What you pay when Part B covers the ER visit

If you are treated in the emergency room and released without being admitted as an inpatient, Part B covers the visit. You pay 20 percent of the Medicare-approved amount for the ER visit, after you meet your annual Part B deductible (which is $240 for 2024).

This means an ER visit that costs $2,000 in Medicare-approved charges would result in you owing $400 (20 percent) after your deductible is met. The hospital may also charge you for specific services — imaging, lab work, medications — as separate line items, each subject to the 20 percent copay.

Many people are surprised by this bill because they think "emergency" means Part A coverage. But Medicare's definition of Part A coverage is based on admission status, not urgency. A life-threatening condition treated in the ER and not resulting in admission still falls under Part B.

The difference between inpatient and observation status

Hospitals sometimes place patients in observation status rather than admitting them as inpatients. This is a gray area that confuses many Medicare beneficiaries. Observation status means the hospital is monitoring you but has not decided whether to admit you as an inpatient. You may stay overnight in a hospital bed, but you are technically still an outpatient.

If you are in observation status and never admitted as an inpatient, Part B covers your visit, not Part A. This matters because observation stays can be expensive — you pay the Part B copay for the observation services, plus 20 percent of any tests or treatments. You do not get the protection of Part A's inpatient deductible and coverage limits.

Ask the hospital staff directly: "Am I being admitted as an inpatient, or am I in observation status?" The answer determines your costs. If you disagree with the hospital's decision to place you in observation rather than admit you, you can file an appeal with Medicare, but this process takes time and does not change your when ready bill.

Emergency room visits at out-of-network hospitals

If you have a Medicare Advantage plan (Part C), your coverage for emergency room visits works differently than Original Medicare. Most Medicare Advantage plans cover emergency room visits at any hospital in the country, even if the hospital is out of network. However, you typically pay a higher copay for out-of-network emergency care.

If you have Original Medicare (Part A and Part B), you can go to any hospital that accepts Medicare, and there is no "network" restriction. Part A and Part B cover emergency room visits at any Medicare-participating hospital, whether it is in your state or across the country.

Before traveling, check whether your hospital of choice accepts Medicare. Most emergency rooms do, but some specialty hospitals or urgent care centers may not. You can search for Medicare-participating hospitals on the Medicare website or call 1-800-MEDICARE to confirm.

What happens if you receive an unexpected bill

After your emergency room visit, you should receive an Explanation of Benefits (EOB) from Medicare within a few weeks. This document shows what Medicare paid and what you owe. Review it carefully to make sure the hospital coded your visit correctly — as inpatient or outpatient.

If you were admitted and the hospital billed the ER visit under Part B instead of Part A, contact the hospital's billing department and ask them to correct it. If they do not respond, you can file a complaint with your state's insurance commissioner or contact Medicare directly at 1-800-MEDICARE.

If you receive a bill for more than your copay or deductible, do not ignore it. Call the hospital and ask for an itemized bill. Some charges may be incorrect, or the hospital may have billed you for services that Medicare should have covered. You have the right to dispute any bill you believe is wrong.

Frequently Asked Questions

If I go to the ER for chest pain but am sent home, does Part A cover it?

No. Part A covers the ER visit only if you are admitted as an inpatient within three days. If you are treated and released, Part B covers the visit, and you pay the Part B copay (20 percent after your deductible). The severity of your condition does not change this rule.

What if I go to the ER, get admitted, but then leave the hospital after one day?

Part A still covers your stay. You pay the Part A inpatient deductible for the entire stay, even if it is just one day. Part A does not charge a daily rate for short stays — you pay the deductible once per benefit period, regardless of length.

Does Part A cover the ambulance ride to the ER?

Part A does not cover ambulance rides. Part B covers medically necessary ambulance transport to a hospital, and you pay 20 percent of the cost after your deductible. Call ahead to confirm the ambulance service accepts Medicare.

If I have a Medicare Advantage plan, do I still use Part A for ER visits?

No. Medicare Advantage plans replace Part A and Part B. Your plan's own rules determine ER coverage, copays, and whether you need prior approval. Check your plan documents or call your plan's customer service before going to the ER.

Can I be billed for the full ER cost if the hospital is out of network?

With Original Medicare, there is no network — all Medicare-participating hospitals are in-network. With a Medicare Advantage plan, you may owe more at an out-of-network hospital, but the plan cannot charge you the full bill. Your out-of-pocket cost is limited by your plan's rules.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.