The Social Security Administration calculates disability using a complex formula based on the average lifetime earnings of the applicant before the disability began, says DisabilitySecrets.com. The pay is not based on how severe the disability is.
If the applicant receives disability benefits from private long-term disability insurance providers, those benefits do not affect Social Security disability benefits, says DisabilitySecrets.com. But if the applicant receives government-regulated disability benefits, such as temporary state disability benefits or workers' compensation benefits, those benefits can affect Social Security disability. An individual cannot receive more than 80 percent of the average amount the applicant earned before he became disabled in Social Security and other disability benefits. If the applicant does receive other benefits, his Social Security disability is reduced.
Veterans benefits and Social Security supplemental income do not reduce Social Security Disability benefits, though those benefits reduce the supplemental income benefits and could make the applicant ineligible to collect Social Security supplemental income benefits, says DisabilitySecrets.com.
The Social Security Administration has a benefit estimate calculator on its website, and it allows individuals to estimate their retirement, survivor benefits and potential disability benefits using retirement dates and the level of any future earnings, says the Advocator Group.