We also frequently get asked the question what is the difference between SSDI and SSI? In both programs, you are entitled to benefits because you are disabled. However, in SSDI, you’ve paid into the system. There have been withholdings out of your paycheck. SSI is disability coverage as well. It differs from SSDI in that it is a welfare-based benefit. One major difference between the two programs is that the benefit for SSI is much lower typically than the benefit for SSDI.