Free Tool
SSDI Back Pay Calculator
Estimate your Social Security Disability back pay using the same formula SSA uses — onset date, 5-month waiting period, 12-month retroactive cap.
Total estimated back pay
$64,780
Retroactive months (pre-application)
7
Back pay months (post-application)
34
How we got this number
- • First eligible payment month = onset (January 2023) + 5-month waiting period → June 2023.
- • SSDI retroactive cap = application month (January 2024) minus 12 months → January 2023.
- • Your 5-month waiting period is more recent than the 12-month retroactive cap, so payments start at the end of the waiting period.
- • Total payable months from June 2023 through approval (November 2026) = 41.
Estimate only. The Established Onset Date your case ultimately secures — and your actual PIA based on lifetime earnings — determine the real check. A free case evaluation with our attorneys gives you a firm number.
What back pay actually covers
Two buckets: retroactive benefits (the months between your established onset date and your application date, capped at 12 for SSDI) and back pay (the months between your application and your approval).
The EOD is the lever. We push for the earliest medically-supportable onset date — that single decision can swing your check by tens of thousands of dollars.
Frequently asked questions
How is SSDI back pay calculated?+
SSDI back pay = your monthly benefit × the number of payable months between your established onset date (plus the 5-month waiting period) and your approval date, capped at 12 months retroactive to your application date.
What is the 5-month waiting period?+
SSDI Title II benefits cannot be paid for the first 5 full calendar months after your established onset date. Payments begin the month after that waiting period ends.
Why is the EOD so important?+
Your Established Onset Date (EOD) is the single biggest dollar lever in a back pay calculation. SSA tends to default to the latest EOD they can defend; an experienced attorney argues for the earliest EOD the medical record supports.
Does this calculator work for SSI?+
No — SSI has no 5-month waiting period and no retroactive months. SSI back pay starts from your application date only. This calculator is for SSDI (Title II) only.