What back pay is
SSDI back pay (past-due benefits) is the money owed for the period between when you became entitled to benefits and when SSA approved your claim. Long approval and appeal times mean it can add up to a large amount.
How the start date works
- Onset date: the date SSA decides your disability began.
- Five-month waiting period: SSDI does not pay for the first five full calendar months after your disability begins.
- Retroactive months: if you applied late, SSA can pay up to 12 months back from your application date, but not before the waiting period ends.
Your payments then start from your entitlement month and continue to the present. Back pay covers everything from that start month to your approval.
How and when it is paid
SSDI back pay is usually paid as one lump sum, though it may arrive in more than one payment. A few months of monthly payments typically begin first, and the lump sum may arrive separately.
| SSDI | SSI | |
|---|---|---|
| Waiting period | 5 full months | None |
| Retroactive before application | Up to 12 months | No. Starts the month after you apply |
| How back pay is paid | Usually a lump sum | Large amounts (more than three times the monthly rate) may be paid in installments |
Attorney fees
If you have a representative with an SSA-approved fee agreement, their fee is the lesser of 25% of your past-due benefits or $9,200, and SSA pays it out of the back pay before sending you the rest.
Taxes
A lump sum can push part of your Social Security into a higher tax bracket. The IRS allows a lump-sum election that spreads the amount across the years it covers, which can lower the tax. See taxes on benefits and IRS Publication 915.