This simple guide explains how your SSDI onset date works, why it’s important, how it’s determined, and what it means for your disability benefits.

Are you applying for Social Security Disability Insurance (SSDI)? It is important to understand the alleged onset date of your disability.
In this guide, we will explain the differences between alleged and established onset dates and why they matter for your SSDI application.
What Does Date of Onset Mean for SSDI?
The onset date is the first day that a claimant meets the definition of disability or statutory blindness defined in the Social Security Act and regulations.
The Social Security Administration uses this date to determine when you became eligible for disability benefits – both medically and financially. It is important to note that the onset date is not simply the first date you met the medical criteria for disability.
Why is the SSDI Onset Date Important?
It is crucial to ensure that your SSDI onset date is calculated correctly because this is when your back-pay benefits will begin. There is also a five-month waiting period for SSDI claims before you can receive monetary benefits.
What is the Alleged Onset Date for SSDI?
The alleged onset date is the date that you, the disability claimant, determined that you became disabled and unable to work your previous job or any job in the national economy.
You will allege your onset date in your initial disability application for Social Security Disability Insurance.
What is the Established Onset Date for SSDI?
The established onset date is the date that the Social Security Administration determines that you became disabled and unable to work.
How Does Social Security Determine Your Onset Date?
The Social Security Administration considers several aspects of your SSDI application to determine your onset date for disability benefits. These include your statement, work history, and relevant medical evidence.
Your Statement
In your medical statement or the Disability Report (Form SSA-3368-BK), you will detail when your disability symptoms started manifesting and when you think you can no longer work due to your disability.
Your Work History
The Social Security Administration will use your previous work history to see when and why you stopped working. If you stopped working for unrelated reasons, such as being laid off, or you chose to quit not based on your disability.
All work history will be factored into your onset date dictated by the Administration. The day that you ended your ability to work, or you have no more ability to perform the substantial gainful activity due to your disability, or the day that the symptoms of your disability became so deliberating, is the day that you should utilize for your alleged onset date.
Also Read: How SSDI Work Credits Affect Your Benefits
Medical Evidence or Other Related Evidence
Your medical team’s reports and medical records can be used as evidence to support the onset date of your disability. It is unlikely that the Social Security Administration or an Administrative Law Judge will grant you an onset date if no medical records support this claim in that period.
For example, if you began seeing a doctor for your disability in March, it would not make sense to allege that your disability started the year prior, absent extenuating circumstances. Your medical records should be able to confirm the time period in which the symptoms of your disability were so bad that you could not work.
Need Help Filling Out Your SSA Function Report? Call Or Email Us!
Please note that every case is unique. We encourage you to contact our Social Security Disability firm at (855) 503-0101 or info@evansdisability.com. Our highly trained attorneys will analyze your SSDI Onset Date, or your case to see what you qualify for and how to apply.
Disability Onset Date FAQ
Common questions about Social Security’s Onset Date.
Why Did Social Security Change My Onset Date?
The Social Security Administration may change your disability onset date after reviewing your disability statement, work history, and relevant medical evidence to better reflect when your disability started or when your disability was expected to last 12 months or longer.
Can You Appeal the Disability Onset Date?
You may be able to appeal a partially favorable disability decision from the Social Security Administration if they find you disabled but disagree with your assessment of when your disability started. We recommend seeking the help of a Disability Attorney experienced in disability issues for your appeal.
What Is an Amended Onset Date for Disability?
An amended onset date for disability is when the Social Security Administration or an Administrative Law Judge disagrees with your alleged onset date due to evidence found in your disability record and changes the date to reflect better when your disability began.
The amended onset date could potentially be earlier or later than the date that you alleged your disability began, depending on the evidence in your disability application.
Can I Change My Disability Onset Date?
You should change your disability onset date after submitting your application only if it makes absolute sense based on your work history, your disability statement, and your relevant medical records.
You want to ensure that you allege the furthest back date that you became eligible for benefits because then you are owed back-pay from the alleged onset date until the date you are approved, minus the five-month waiting period for Social Security Disability Insurance.
How Hard Is It to Change My SSDI Onset Date?
Suppose the Administrative Law Judge, during your court hearing regarding your disability application, changes your SSDI Onset date. In that case, it is possible to appeal their decision if they issue you a “partially favorable” decision.
However, if the Social Security Administration gives you a “fully favorable” decision with a different Onset date, it will likely be more difficult to appeal the onset date.