One of Medicare’s most important benefits is helping to cover your expenses if you need to be hospitalized. But what exactly is covered, and how much do you pay?

Medicare helps cover certain services and supplies in hospitals. To get the full range of benefits, you must have both Medicare Part A, which is hospital insurance, and Part B, which is medical insurance.

What you pay depends on whether you’re an inpatient or an outpatient. Staying overnight in a hospital doesn’t always mean you’re an inpatient. You’re an inpatient on the day the doctor formally admits you, with a doctor’s order.

You’re an outpatient if you haven’t been formally admitted as an inpatient, even if you’re getting emergency department services, observation services, outpatient surgery, lab tests, or x-rays.

If you aren’t sure whether you’re an inpatient or an outpatient, you or your family should ask your doctor or the hospital staff. Or you can call Medicare at 1-800-MEDICARE (1-800-633-4227).

If you’re admitted as an inpatient, Part A will help cover your stay. This generally includes a semi-private room, meals, general nursing care, drugs, and other hospital services and supplies.

Part A covers your care in acute care hospitals, critical access hospitals, inpatient rehabilitation facilities, long-term care hospitals, and psychiatric facilities.

How much you’ll pay depends partly on how long you stay.

Medicare pays for inpatient hospital care based on “benefit periods.” A benefit period begins the day you’re admitted to a hospital – and ends when you haven’t had any inpatient hospital care for 60 days in a row.

You can have more than one hospital stay within the same benefit period. There’s a limit on how many patient days Medicare will cover during a benefit period, but there’s no limit on the number of benefit periods you can have over your lifetime.

How much comes out of your pocket when you’re in the hospital?

Part A has a deductible, which is $1,216 in 2014. You pay this deductible at the beginning of each new benefit period.

After you’ve paid that, there’s no co-payment for days 1 through 60 of each benefit period. For days 61through 90 of each benefit period, there’s a co-pay of $304 per day.

You also have 60 “lifetime reserve days.” These can be used after day 90 of each benefit period, and your co-pay is $608 per day in 2014. After you use up these “lifetime reserve days,” you must pay all costs yourself.

Keep in mind that Part A doesn’t cover doctor fees or other medical services. That’s where Part B comes in.

To get Part B, you must pay a monthly premium, which for most people is $104.90 per month this year.

You’ll also pay 20 percent of the Medicare-approved amount for most doctor services while you’re an inpatient. Part B also helps cover outpatient costs, such as doctors’ fees, emergency and observation services, lab tests, and X-rays.

Finally, here are some things Medicare doesn’t cover in the hospital:

* Private-duty nursing;

* A telephone or television;

* Personal items like toothpaste or razors;

* A private room, unless it’s medically necessary.

To learn more about Medicare benefits, please refer to your 2014 Medicare & You handbook, go online to www.medicare.gov, or contact our 1-800-MEDICARE customer service professionals who can help you with specific concerns before a hospital stay.

David Sayen is Medicare’s regional administrator for Arizona, California, Nevada, Hawaii, and the Pacific Territories. You can always get answers to your Medicare questions by calling 1-800-MEDICARE (1-800-633-4227).