Back payments for SSI are calculated for the months that are between the date the applicant applied for benefits and the date of approval. For SSDI back payments, there's a five-month waiting period, so payments are calculated from after the waiting period has ended to the approval date.
There is another kind of back payment that may be available to applicants for SSDI benefits, called retroactive benefits. These payments are made for the months between the date the applicant became disabled and the date the applicant applied for SSDI benefits.
The type of back payment an individual can receive is dependent upon the type of benefits she is hoping to receive. SSI benefits are for lower-income individuals, while SSDI benefits are for those who have some type of work history. It is possible for individuals to receive both types of benefits.
For individuals who receive SSI benefits, the payments usually begin the first full month after the applicant is approved. If the applicant is deemed to be “presumptively disabled,” she can begin receiving benefits during the time frame in which her application is being processed. For individuals receiving SSDI, there are a few different factors affecting when benefits begin, including the date of disability, the application date and the five-month waiting period.