Your Guide to SSDI Forms SSA-16, SSA-3368 & SSA-3373

Applying for Social Security Disability Insurance (SSDI) can feel like a lot of paperwork all at once. You are asked to remember dates, list doctors and medications, describe past jobs, and explain how your health affects everyday life. If you are doing this while dealing with pain, fatigue, or brain fog, it can feel like too much.

This article walks you through the three core Social Security disability application forms that are part of an SSDI claim. These three forms are your disability paperwork trio. It covers what each form is for, how to answer questions, what to gather before you start, and how to avoid common mistakes that cause delays. 

Learn how to give clear, complete, and specific answers that help reviewers decide your claim.

The Main SSDI Forms in Your Disability Application (SSA-16, SSA-3368, SSA-3373)

The three main forms in your disability claim help the Social Security Administration (SSA) and your state Disability Determination Services (DDS) office understand your work history, your medical situation, and what a normal day is like for you. When your forms are clear and consistent, it’s easier for the SSA and DDS to evaluate your claim.

The SSA handles the intake side of your claim, including your identity, basic eligibility, and work history. DDS reviewers make the medical decision on claims with the information you provide. They use your medical records to see if you meet the SSA’s definition of disability, which is having a condition that prevents you from working for at least 12 months or is expected to result in death.

Reviewers aren’t looking for perfect writing. They need a clear timeline, facts, and details that prove you meet the disability rule. The three main disability application forms allow them to collect medical evidence in your case and understand your limits.

Here is a quick explanation of each form:

• Form SSA-16 is the main application. It covers your basics, your work and earnings, and key dates like when you became unable to work.
• Form SSA-3368 is the Adult Disability Report. It collects your medical sources, tests, medications, work history, and condition details.
• Form SSA-3373 is the Function Report. It gives a snapshot of how your condition affects your daily activities and ability to work.

Overview of SSDI Forms SSA-16, SSA-3368 and SSA-3373

Form SSA-16: The Main SSDI Application

You start your SSDI claim with Form SSA-16 - the main application. It’s the form that sets your basic timeline. It will cover your personal information, earnings, and the dates and work details the SSA needs to evaluate non-medical eligibility. You can apply online, over the phone, or in person.

Answer each question fully and honestly. If you don’t remember a detail or date, use your best estimate and explain that it’s an estimate. Don’t leave any questions blank.

Form SSA-3368: The Adult Disability Report

Form SSA-3368 collects your medical and work details so DDS reviewers can evaluate your claim. It asks for your provider list, treatment history, medications, tests, hospitalizations, symptoms, and how your conditions limit you. It also asks for job descriptions so the DDS understands what you did on the job.

This form is long because it’s doing several jobs at once. It helps the DDS request records from the right places, understand how your conditions have changed over time, and see what limits you are describing. To complete it, you need a provider list, a medication list, and your basic job history. Use the preparation section below to gather needed items.

Form SSA-3373: The Function Report

Form SSA-3373 is called a function report because it focuses on how you function day-to-day. It asks about your routines and the daily tasks you can and can’t do.

When you describe limitations, you’re not being judged as a person. You are describing what your body and mind can realistically handle every day. You answer questions about your typical day, personal care, meals, household tasks, errands, going out, social activity, focus and attention, and handling stress or changes.

Cross-Checking: How Your Answers Are Compared

Creating a Consistent Story

Reviewers are looking for a consistent story. That doesn’t mean your health is the same every day or you write the same sentence three times. It means the big facts should fit together.

Your timelines, work history, and why and when work stopped working should be the same in the forms. Your functional limits should match your description of symptoms, treatment, and daily life.

When your answers don’t match, it doesn’t automatically mean a denial. But it can lead to follow-up requests, extra forms, or delays. Make it easy for a reviewer to follow your timeline and limits without guessing.

Cross-Checking Facts

Use this as a practical checklist while you fill out the forms. It shows the most common areas reviewers compare.

Timeline

Your onset date on the SSA-16 must match your symptom timeline on the SSA-3368 and your typical day on the SSA-3373. The date you could no longer work should align with dates when symptoms became limiting.

Work

The date you last worked and stopped working on the SSA-16 must match the job dates you list on the SSA-3368. The reason you stopped working should make sense when compared to the type of work you did and what that work required.

Treatment

Medications and treatment listed on the SSA-3368 must connect to side effects and daily impacts described on the SSA-3373. If treatment causes fatigue, pain, brain fog, or other limits, those effects should be explained in statements about how you can function daily.

Function

The limits you describe on the SSA-3368 must align with the daily activities you report on the SSA-3373. Be careful not to describe activities in a way that suggests you can do more than your condition allows.

Support

If you report help from others on the SSA-3373, explain why that help is needed on the SSA-3368. Describe what tasks are hard and why. This helps the reader understand the level of difficulty you deal with day to day.

Common Contradictions in SSDI Forms (and How to Avoid Them)

Here are common contradictions that reviewers see in disability applications and how you can avoid them. You’re giving context so your answers are easy to interpret, not defending yourself.

“Stopped work due to symptoms” vs. “work history suggests full duties continued.”

How to avoid this: Clarify reduced duties, reduced hours, attendance issues, or a gradual decline in work before the end date. Add a line such as, “In the last three months, I missed two days a week and could not keep pace, even with lighter tasks.”

“No side effects” vs. “sleeping most of the day.”

How to avoid this: Explain whether your tiredness is from the condition or from medication. You can write, “My condition causes fatigue most days, and the tiredness got worse after my evening dose of medicine was increased.”

“Can’t stand more than five minutes” vs. “shops for an hour.”

How to avoid this: Explain if you need breaks, mobility aids, or help from other people to do your activities. Then describe what happens after the activity (do you need to rest? How long?) For example, “I shop using a cart for walking support and stop every few minutes. Afterward, I need to lie down for the rest of the day.”

“I do my own cooking” vs. “I can’t use my hands well.”

How to avoid this: Describe modifications you need, like microwaving because it’s faster, using precut foods, sitting while preparing food, or getting help with chopping. A line such as, “Cooking means microwaving meals and using precut foods, because chopping and gripping tools increases pain.”

“I don’t go out” vs. “I drive daily.”

How to avoid this: Clarify the type and length of trips and if someone comes with you. You can say, “Driving is limited to short, five-minute trips to appointments and I avoid other outings.”

“I can focus fine” vs. “I can’t complete tasks.”

How to avoid this: Separate your ability from your endurance. “I can focus for about 10 minutes, then I lose track and need reminders or breaks, especially when my symptoms flare.”

“I lift 20 pounds” vs. “I can’t lift at work.”

How to avoid this: Explain the difference between lifting occasionally and lifting repeatedly for hours. Note how much of the time you lifted things at work, like every hour or half of the day. Activities are not the same as sustained work demands. Also, add a line about the recovery time you need if relevant.

“I take care of kids” vs. “I need help with daily tasks.”

How to avoid this: Describe what care looks like and what support you need. For example, “I watch my children from a chair most of the day and another adult drives, bathes them, and cooks most meals.”

Use these questions to help give short answers with specifics:

• Frequency: How often does it happen?
• Duration: How long can you do it before symptoms increase?
• Assistance: Who helps, or what tools you use?
• Modifications: Breaks, sitting, simplified tasks, slower pace.
• After effects: What happens later? (pain, fatigue, recovery time)

What To Gather Before You Fill Out SSDI Forms SSA-16, SSA-3368 and SSA-3373

You can make this process easier by gathering the needed information before you sit down to fill anything out. You don’t need every detail from your records, just a list that helps you answer questions without stopping every two minutes.

If you don’t know the exact dates, estimate the month and year. It is okay to say “approximately” when you’re not sure. Your entries just need to be legible and support your story.

Here’s what you need to complete disability forms:

• Medical Providers and Clinics: Names, addresses, and phone numbers for doctors, clinics, therapists, and hospitals.
• Approximate Visit Dates: Month and year is enough if you do not know the exact date.
• Medications: Name, dose if you know it, and who prescribes it.
• Tests and Treatment: Imaging, labs, therapy, injections, surgeries, hospital stays, and approximate dates.
• Job History Basics: Employer names, job titles, dates, and what the job required physically and mentally.
• A Support Person: Someone who knows how you function day-to-day, in case reviewers ask for a third-party report.
• Basic Identity and Banking Details: Identity documents and banking information for direct deposit.

Wondering if you’re eligible for SSDI? Need help gathering records?

Completing High-Impact Fields in Form SSA-16

Timeline of Onset Date and Last Worked Date

Your onset date and your last worked date are two of the most important entries on Form SSA-16. The onset date is the date you became unable to work at a substantial level because of your condition. The SSA describes Substantial Gainful Activity (SGA) in 2026 as earning $1,690 a month or $2,830 a month if you’re blind.

The date you last worked is the last day you worked on a job, even if it was part time or you were struggling. If you stopped working gradually, explain that briefly in the remarks section. 

Examples:

• Onset date: “March 2024 (or 3/2024). My symptoms worsened and I could not keep a regular schedule or complete tasks without frequent breaks.”

• Stopped working: “May 15, 2024 (or 5/15/2024). I stopped working because my pain increased causing me to miss shifts. My employer couldn’t modify my job to fit my restrictions.”

Answering Questions About Work Earnings and Other Benefits

Form SSA-16 asks about your work, earnings, and other benefits if relevant. You need to provide your basic eligibility information with enough detail that reviewers won’t need to follow up with you. Answer every question even if your answer is “no” or “does not apply.”

If you’re unsure about earnings or dates, look up the information instead of guessing. Or use your best estimate and note that it’s an estimate.

Where to clarify earnings:

• Recent pay stubs
• W-2 forms or tax returns
• Benefit letters from other programs
• Calendars, emails, or old resumes with employers and job dates

How to Use the Remarks Section

The remarks section is useful when you need to clarify something that would be confusing otherwise. It’s not the place for a long story. Use short, factual notes (one or two sentences) connected to dates when possible. Helpful remarks explain timelines, why work ended, or your main limitations.

Examples of notes in the remarks section:

• “My symptoms worsened gradually from late 2023 to spring of 2024. I tried working reduced hours with lighter duties before I stopped working on 5/15/2024.”
• “My main limitations are standing more than 10 minutes, lifting over 10 pounds, and staying on task longer than short periods. I need frequent breaks and help with errands most weeks.”

Completing the Adult Disability Report

Making Medical Records Requests Easy

When you complete the Adult Disability Report, you want to make requesting records easy. To do this, list every provider you’ve seen for your disabling conditions, including clinics, urgent care, emergency room visits, specialists, therapists, and hospital systems. It’s better to include a provider you’re unsure about than to miss a place that may have important records.

Use a consistent entry format so it’s easy to scan. If you don’t remember a provider’s name, list the clinic name and location. Make sure your information matches answers on the Function Report.

Example provider entry format:

• Provider or clinic name. City and state.
• Address and phone number.
• Dates seen. Month and year to month and year, approximate if needed.
• Reason. Condition treated, testing, therapy, and follow up.

Example entry:

• “River Valley Orthopedics, Fresno CA. 123 Main Street, 555-555-5555. Seen approximately from 3/2023 to 11/2024 for back pain, leg numbness, imaging review, and injections.”

Medications, Tests, and Treatment History

List your medications as completely as you can. Include the medication name, dose, who prescribes it, and what it’s for. If you don’t know the dose, list the medication name and prescribing doctor. For tests and therapies, list what was done, where it was done, and the approximate timing.

If you stopped taking medication, briefly explain why such as side effects, lack of benefit, or a change in your treatment plan. Remember, you’re giving a record of what happened, not arguing your case.

Example medication line:

• “Stopped taking gabapentin on 10/2024 because of dizziness and daytime sleepiness. My doctor changed my medication after my follow up appointment.”

For your treatment history, list the treatments you’ve tried over time, even if they didn’t help. This includes physical therapy, counseling, injections, procedures, hospital visits, or other ongoing care. Include where the treatment happened, how long it lasted, and if it improved your symptoms, they stayed the same, or it caused problems. If a treatment was stopped, note why, such as lack of improvement, side effects, or your provider changing the plan.

Work History Including Job Duties and Demands

When you describe your past work, explain what your work required day after day. This includes physical demands like lifting, carrying, standing, walking, bending, reaching, and using your hands. It also includes mental demands like keeping pace, multitasking, attention to detail, following instructions, interacting with others, and staying on schedule.

Use measurable details when possible. Instead of saying “I worked in a warehouse,” describe what you lifted, how long you stood, and your pace. Use short, factual statements instead of long paragraphs.

Example of a detailed answer:

Instead of writing “Warehouse worker,” say “Loaded and moved boxes, typically weighing 30 to 50 pounds. Stood and walked most of the seven-hour shift. Repeated bending and reaching. Used a handheld scanner and met hourly pace targets.”

How to Describe Your Limits on SSDI Forms Without Undermining Your Claim

This is where you translate your symptoms into limits. “I have pain” or “I have anxiety” is not enough by itself, because it doesn’t show what you can and cannot do. Describe your limits using frequency, duration, triggers, and recovery time. If symptoms vary, describe what happens on most days and what happens on bad days.

Avoid vague statements like “I can’t work.” Instead, describe what happens when you try to work. For example, do you need to change positions every few minutes, miss appointments due to flare ups, or need reminders to complete tasks?

A template for these sections is “I can do X for Y minutes before Z happens.”

Example:

• “I can stand for about 10 minutes before back pain and leg numbness increase and I need to sit or lie down. After activity, I often need an hour or more to recover.”

How to Complete the Function Report Clearly

Complete the Function Report honestly and with specifics. Don’t write a personal essay. Focus on how you manage daily activities most of the time. Include the help you need, breaks you take and the pace you can manage. Avoid undermining earlier answers with conflicting statements.

Describing a Typical Day

When you complete the “typical day” section, describe it in parts of the day like morning, afternoon, and evening. Explain what you can do, what you cannot do, and what help or recovery you need.

Explain “most days” and “bad days” if your symptoms fluctuate. Small details like needing reminders, resting between tasks, or needing someone else to drive can help the reader understand your functioning.

Typical day example of physical limitations:

“Most days I wake up and need time to loosen up before moving around. I can make an easy breakfast, then I rest with my legs elevated. I do one small chore like wiping counters, then I need a break. I leave home mainly for appointments and usually need someone to drive me. By afternoon, pain and fatigue increase and I lie down for one to two hours. I rest most evenings and only walk a little in my home.”

Typical day example of mental or cognitive limitations:

“Most days I wake up tired and need reminders to take my medicine. I can do one task at a time, like washing a few dishes, but I lose track if there are multiple steps. I rest often because stress and noise make my symptoms worse. I avoid doing errands alone and limit phone calls because I get overwhelmed. In the evening, I try to prepare an easy meal and then I need quiet time. I go to bed early.”

Personal Care: Chores, Meals, and Errands

It can be hard to answer these questions if you can do these activities sometimes, but not regularly. Describe how you do the tasks with modifications like doing tasks more slowly, taking breaks, using a stool, or getting help from another person. Those details are important.

Focus on safety and practicality when you answer. If it’s hard to take a shower, say what makes it hard and what you do instead. If your cooking is limited, explain if you microwave meals, use delivery, or rely on someone else. If you can only run errands with help, name the help and what happens after you do errands.

Examples of explaining tasks:

• “I can shower, but I need a shower chair because standing causes dizziness.”
• “I can make food if it’s easy like microwaving meals. Chopping and standing at the counter increases pain.”
• “I can only shop with help. I use the cart for support, take breaks, and I usually need to rest afterward.”

Questions About Social Life, Focus, and Handling Stress

This section is not about your personality. It’s about what happens when you try to focus, follow instructions, interact with others, or handle stress. Use brief, specific examples. Describe what happens, how often it happens, and what helps, even if your answer is “I avoid it.”

If you struggle with tasks that have multiple steps, say so. If stress triggers symptoms, say what happens and what you do to manage it. If you have trouble being around people, explain what happens, like you leave early, need someone with you, or miss appointments.

Examples:

• “I have trouble following multi-step instructions. I need written notes or reminders, and I still forget steps several times a week.”
• “I can focus for about 10 minutes before my mind wanders or my symptoms increase. I need breaks and I often can’t finish tasks without help.”
• “Stress makes my symptoms worse. When plans change, I become overwhelmed and may need to lie down or be alone for hours.”
• “I avoid crowded places. If I have to go, I go with someone and I leave early.”
• “I struggle to get things done. Even easy tasks take a long time and I need time to recover afterward.”

Medications and Side Effects

If you have side effects, list them in functional terms rather than just say you have them. The reviewer needs to understand what the side effect does to your day.

Explain how side effects like sleepiness, dizziness, nausea, slowed thinking, tremors, or trouble concentrating affect your day. Do you need to take naps, avoid driving, need help with errands, or take longer to complete tasks? Say that.

Examples of side effects and their impacts:

• “My medicine makes me sleepy all day. I need to lie down most afternoons.”
• “My medication causes dizziness, especially when I’m standing. I use support and avoid driving.”
• “My medication slows my thinking. I take longer to follow instructions and I need reminders.”

Common Mistakes That Slow Claims

Inconsistent answers

Below are common mistakes and ways to avoid them. If you notice one of these common mistakes in your forms, add a clarifying line or update an estimate.

• Dates don’t match. Choose your best estimate and update across entries.
• The onset date is unclear. Add the month and year and a brief reason for your work limits at that time.
• Date last worked differs from job dates. Confirm the last day you worked and adjust job end dates if needed.
• The reason work stopped does not match job demands. Add one line about reduced duties, missed shifts, or inability to keep a steady pace.
• Your activities suggest more ability than your limits describe. Add the breaks, help and modifications you need plus recovery you need after.
• The provider list is missing key clinics. Add urgent care, emergency room visits, specialists, and therapy locations.
• The medication list does not match the treatment narrative. Update with current medications and medications you recently stopped taking.
• Symptoms are listed without functional limits. Add frequency, duration, and recovery time.
• Work history is too vague. Add details about lifting, standing, keeping pace, multitasking, and attendance.
• A typical day reads like a good day only. Use “most days” and add what changes on bad days.

Quick Fixes for Common Mistakes

These quick changes can make your documents easier to read and reduce follow-up requests.

• Leaving blanks. Write “none” or “does not apply.”
• Overly vague answers. Add one concrete example.
• Long stories. Use short, factual sentences.
• Missing provider contact info. Add the clinic phone and address if possible.
• Missing date ranges. Use month and year estimates.
• Listing only one provider when you saw several. Add all treatment sources you can recall.
• Skipping mental health treatment details when relevant. List therapy, psychiatry, and medications with dates.
• Forgetting hospital or emergency visits. Add approximate dates and the facility name.
• Not explaining needed modifications for activities. Add “with help,” “with breaks,” “using a stool,” or “only on good days.”
• Not keeping a copy of what you wrote. Save a copy so you can respond consistently if asked later.

Quality Check Before You Submit

• Are my onset and last worked dates the same everywhere?
• Do my job dates and duties match what I said about when I stopped working?
• Are all medical providers listed with contact info and approximate dates?
• Do my medications match what I described about side effects and daily impact?
• Did I avoid blanks using none or does not apply?
• Did I include frequency, duration and examples for my main limits?
• Did I keep remarks short and factual?

Where You Will Complete Forms

Where you fill out the forms depends on how you apply. If you apply online, you do some forms during the application. Other forms may be requested later and can be completed online or by mail.

If you apply by phone or in person, SSA representatives help you fill out the forms and then send additional forms to finish after checking your eligibility.

Choose the option that works best for you. Online applications let you save and take breaks. Phone or in person may work better if typing is difficult or you don’t have a computer and Internet access.

What Happens After You Apply

After you apply, the SSA receives your claim and confirms your eligibility. The claim is then sent to your state DDS office for the medical review. DDS requests records from the providers you listed, reviews medical evidence, and may contact you for more information.

In some cases, DDS reviewers schedule a consultative exam, which is a short medical exam with a provider they select and pay for. You may also be asked to complete additional forms or clarify dates and treatment sources.

Requests for more information typically come in the mail so open mail from the SSA and DDS right away. Mark deadlines for requests on a calendar and respond with what you have, even if some details are approximate.

It typically takes five to eight months to get a decision after your initial application. If you’re denied, you have several chances to appeal.

Your Next Step

Use the preparation checklist to gather your provider list, medications, and job history. Then complete the forms one section at a time. When you finish, run through the quality check questions before you submit.

Need help? Advocate’s disability experts and clinical staff can help you submit the strongest application and respond to requests.