When you apply for benefits from the U.S. Social Security Administration, your eligibility period doesn't necessarily start the day you file your application. If you qualified for benefits before the date you applied, you may have back benefits coming your way.
The U.S. Social Security Administration defines retroactive benefits as the "monthly benefits that you may be entitled to before the month you actually apply, if you meet the requirements." In other words, if you are approved for benefits a month or more after becoming eligible, the SSA will pay those benefits to you anyway. However, the total retroactive pay you receive depends on the type of benefits you apply for and the timing of your application.
You must be at least 65 years old to receive your full Social Security retirement benefits and 62 years old to receive benefits at a reduced amount, as of 2015. The longer you wait to claim benefits, the more your benefits will be. However, you are not required to apply for benefits once you reach retirement age. You can apply anytime afterward. However, the government only pays up to six months in retroactive benefits and you must retire at full retirement age. For example, if you reached full retirement age in March of 2015 but didn't apply until one year later, in March of 2016, your retroactive benefits date back to September 2015. If you applied less than six months after your full retirement age, your retroactive benefits only go back to the month of your birthday. So if you applied for benefits three months after turning 65, you are only eligible for three months of retroactive pay.
If you die, your spouse can receive Social Security benefits based on your record, known as survivor benefits. She will receive full benefits if she files when she reaches full retirement age, regardless of her circumstances. She will also be eligible for up to six months of retroactive pay. If your spouse applies when she is younger than full retirement age but older than 60, she will receive reduced benefits. She can apply for reduced benefits as soon as 50 if she is disabled, or at any age if she's the caregiver of a child under 16 or child of any age who became disabled before 22. Disabled surviving spouses who file a certificate of election are eligible for up to one year of retroactive pay.
When it comes to Social Security disability benefits, you can receive up to 12 months of retroactive pay. However, there is a five-month waiting period and retroactive payments are not granted for this period. For example, if you became disabled in January of 2015 and applied for benefits in June of that same year, you would only be eligible for one month of retroactive pay because five of the previous six months are treated as the waiting period. You also won't receive retroactive pay for any months you were not disabled, even if that period falls within the 12-month window.