QUESTION: I’ve only been working for a few years, and I’m wondering how I earn Social Security benefits. What are credits and how many do I need to qualify for benefits?

ANSWER: Your total yearly earnings are used to calculate your Social Security credits. “Credits” are the units used to measure whether you qualify for Social Security benefits. The amount needed for a credit in 2015 is $1,220. You can earn a maximum of four credits for any year. The amount needed to earn one credit increases automatically each year when average wages increase.

You must earn a certain number of credits to qualify for Social Security benefits. The number of credits you need depends on your age when you apply and the type of benefit for which you are applying. No one needs more than 40 credits for any Social Security benefit.

QUESTION: I served in the military, and I’ll receive a military pension when I retire. Will that affect my Social Security benefits?

ANSWER: You can get both Social Security retirement benefits and military retirement at the same time. Generally, we don’t reduce your Social Security benefits because of your military benefits. When you’re ready to apply for Social Security retirement benefits, go to www.socialsecurity.gov/applyonline. This is the fastest and easiest way to apply. For your convenience, you can always save your progress during your application and complete it later. And thank you for your military service.

QUESTION: I need proof that I receive Medicare benefits. Where can I get a letter proving that?

ANSWER: If you need proof that you get Social Security benefits, Supplemental Security Income or Medicare, get an instant benefit verification letter online by using your personal my Social Security account. If you don’t receive benefits, your letter will serve as proof that you don’t receive benefits. If you recently applied for benefits, the letter will make that clear as well.

The information on your benefit verification letter will include information about your situation.

This column was prepared by the Social Security Administration. For fast answers to specific Social Security questions, contact Social Security toll-free at 800-772-1213 or visit www.socialsecurity.gov.