Many SSI claimants receive back payments of disability benefits when they are approved for SSI. The amount of backpay that you receive depends on how many months have passed since you filed your SSI application, and also on whether Social Security agrees that you were disabled on your application date. You cannot receive retroactive SSI benefits back to a date before your application date, even if you were disabled at that time (this is different than for SSDI backpay.).
The amount of your backpay will depend on your application date, your state’s monthly SSI benefit amount during the backpay months, and the income you had during the backpay months (each month has to be looked at individually).
Social Security may find that you are disabled and entitled to SSI, but it may disagree with you about the date you became disabled. If Social Security thinks that you became disabled after you applied for SSI and while you were waiting for a decision, then it will issue backpay to you only from the first full month following the date that it finds you became disabled. That date is called your "established onset date."
If Social Security approves your SSI application and agrees with you that you were disabled on the date you filed your application, the agency will pay you SSI benefits for every month from the first full month after the day you filed your SSI application. The amount of the SSI back pay will depend on your income.
You can get up to two months of additional SSI payments if you contacted Social Security by phone or in person to ask about filing for SSI up to two months before the date you actually filed your SSI application. The date you contacted Social Security is your "protective filing date."
If your SSI backpay award is less than three times the maximum monthly SSI benefit amount for your state, Social Security will pay you all of your backpay in one lump sum. In 2015, the federal monthly benefit amount is $733, but most states add supplements to that amount, so the benefit amount that applies to you may be different.
If your backpay award is more than three times the maximum monthly SSI amount for your state, Social Security will issue your payment in up to three installments, six months apart. The first two installments cannot be more than three times the maximum monthly benefit amount, but Social Security will pay the balance in the third installment, no matter how large it is. For example, if Social Security owes you $8,000 in SSI backpay and you live in a state where the maximum monthly benefit amount is $733, then your first and second installments would be $2,199 ($733 x 3), and your third installment would be $3,602.
Social Security may give you a larger installment payment if you have current debts for food, housing (including the purchase of a home), clothing, or medical expenses that you are solely responsible for and that you cannot pay without an increase in the backpay amount.
Social Security will issue backpay in one lump sum only if you have a terminal illness and are not expected to live longer than six months, or if you are no longer eligible for SSI and are not expected to become eligible again for 12 months.