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EFW2 Format Guide: Layout, Records and Rules for 2026

November 8, 2026 Tax Form Hero Team 5 min read

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Geometric blocks represent fixed-width EFW2 records

EFW2 is the Social Security Administration’s electronic file format for annual Form W-2 Copy A data. SSA defines it alongside EFW2C, the matching format for Form W-2c corrections. An EFW2 file is a fixed-length ASCII text file. Every record is 512 bytes, and the records follow a set order from an RA record to an RF record. This guide explains that layout, the field rules, and the checks to run before a wage file reaches SSA.

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Key Takeaways

EFW2 is SSA’s fixed-length text format for W-2 Copy A data. Each record is 512 bytes, and the file must be ASCII.
A file has nine record types. RA must come first, RF must come last and appear once, and RE, RW and RT are required in between.
Text fields are left justified and blank filled. Money fields are right justified, zero filled, unsigned, and carry no punctuation.
Test every file in AccuWage Online before upload. If SSA rejects a file, you have 45 days to send the corrected, retested file.
For tax year 2026, SSA Publication 42-007 defines EFW2 and Publication 42-014 defines EFW2C.

TaxFormHero is an IRS-authorized e-filing platform, so you can e-file Form W-2 online without paper or a subscription.

What EFW2 is and who needs it

EFW2 is a specification, not a program. It tells payroll software, in-house developers and service bureaus how to arrange W-2 data so SSA can read it automatically. SSA’s software developer instructions state that developers of payroll and tax reporting software must follow the EFW2 and EFW2C formats when they submit wage data electronically.

You meet EFW2 in three situations:

Your payroll system exports a wage file and you upload it to SSA.
You build a conversion from payroll data into the format yourself.
A file you uploaded was rejected and you need to read the error.

If you only enter W-2 data into a web form or spreadsheet template, the filing platform builds the EFW2 file for you. You still benefit from knowing the structure, because rejections and reconciliation problems come back to it.

The e-filing requirement matters here too. SSA’s 2026 publication says employers submitting 10 or more information returns, such as W-2 or 1099 forms, in a calendar year must file them electronically unless the IRS grants a waiver. A penalty may apply if you do not.

Which SSA publications apply to tax year 2026

SSA lists its W-2 and W-2c filing specifications on one page, with tax year 2026 as the current set and tax year 2025 also listed. For tax year 2026:

Format	Used for	SSA publication
EFW2	Annual Form W-2 Copy A data	Publication 42-007
EFW2C	Annual Form W-2c Copy A data	Publication 42-014

The EFW2 publication for 2026 is dated September 14, 2026. Use the edition for the tax year you are filing, not last year’s copy. The 2026 layout adds changes to employer and wage records and extra money fields in optional records, so compare the current SSA documentation with your export instead of carrying over old positions. Our own guide to the three new 2026 W-2 codes covers the form-side changes that feed into this.

The filing due date is part of the same publication. SSA states that 2026 Forms W-2 and W-3 are due to SSA on February 1, 2027, on paper or electronically. Our W-2 deadline guide covers how payroll teams plan around it.

How an EFW2 file is laid out

An EFW2 file is plain text. Every data record is 512 positions long, and a record that is shorter or longer breaks the layout. The file holds nine record types, each with a two-letter code.

Record	Name	Status	What it holds
RA	Submitter	Required, must be first	Who is sending the file
RE	Employer	Required	The employer the following wages belong to
RW	Employee	Required	Wage and tax data for one employee
RO	Employee Optional	Optional	Additional employee data
RS	State	Optional	State wage and tax data for an employee
RT	Total	Required	Totals for the employer’s RW records
RU	Total Optional	Optional	Totals for the RO records
RV	State Total	Optional	Totals for the RS records
RF	Final	Required, last, once only	Closes the file

Order and structure

The file is a sequence, not a collection. The RA record opens it. An RE record opens each employer. The RW records for that employer’s employees follow, with any RO and RS records after the employee they describe. The RT record closes the employer’s wage section. The RF record ends the whole file and appears one time.

EFW2 record sequence from RA through RF

SSA requires that a file contain the complete submission from RA through RF. A partial file, or a file that stops before RF, cannot be processed. If you file for several employers, each one gets its own RE through RT block inside a single submission.

Why the 512-byte rule matters

Because the format has no delimiters, position is the only thing that tells SSA what a value means. A name that slips one column to the right turns the next field into garbage. Most formatting rejections come from a shifted field, a short record or a stray character, not from wrong tax data.

Field and formatting rules

SSA’s publication sets the rules for how values are written inside each record. They are short, and they cause most of the avoidable errors.

Text and numeric-text fields

Alpha and alphanumeric fields are left justified and filled with blanks. Write the value starting at the first position of the field. Pad the rest with spaces to the field’s full length.

Money fields

SSA’s rules for money fields are specific:

Use only digits. No dollar signs, commas, periods or minus signs.
Do not use signed amounts.
Include dollars and cents. The decimal point is assumed, not typed.
Right justify and fill with leading zeros.
When no amount is reported, enter zeros, never blanks.

An example shows the effect. A wage of $52,340.75 becomes 5234075 with the decimal implied, then zero filled on the left to the length of the field. A field of 11 positions would read 00005234075. The field length in the publication is the one that governs, so always check it for the specific field.

File encoding

The file must be in ASCII format. Text editors and spreadsheet exports sometimes save with other encodings or add special characters. Names with accents, curly quotes copied from a document and line-break characters inside a record are common causes of trouble. Clean them before you build the file.

Wage limits for 2026

Two 2026 limits appear in SSA’s publication. The Social Security wage base maximum is $184,500, and the maximum Social Security tips amount is $11,439.00. Totals above these figures in the related fields point to a mapping error, so build them into your validation.

Mapping payroll data to EFW2 positions

Most bad files start with a bad mapping, not a bad layout. Payroll systems hold many pay fields with names like gross pay or total pay. None of them is automatically the right number for Box 1, Box 3 or Box 5 of the W-2. Box 1 federal wages, Social Security wages and Medicare wages differ because of pre-tax deductions and benefit treatment.

Build a written map before you export:

List each W-2 box you report.
Name the payroll source field or calculation that feeds it.
Note the tax year the field applies to, since codes and positions change.
Record any transformation, such as removing the decimal or capping at the wage base.
Set a control total you can compare against the payroll register.

The map also protects you when employees leave and payroll staff change. Anyone can read it and see why a figure landed where it did.

Reconcile by employer, not only at the end

When you file for more than one EIN, a correct grand total can still hide a problem. An employee placed under the wrong RE record changes two employer totals and leaves the file total unchanged. Check each RE-to-RT block against that employer’s payroll register. Our W-2 filing workflow with an exception queue shows one way to catch these before the deadline.

Test the file in AccuWage Online

SSA tells filers to test wage files in AccuWage Online before upload. Its software instructions say Business Services Online no longer accepts incorrectly formatted W-2 files, and that testing each year greatly reduces rejections.

A practical test routine:

Build the file from RA through RF as one text file.
Run it through AccuWage Online.
Fix every error it reports in the source mapping, not by hand-editing the file. Hand edits disappear the next time you export.
Run it again until it is clean.
Compare the RT totals with your payroll register.
Only then upload.

Keep the tested file and the report together with your control totals. If an employee disputes a figure later, you have the trail.

Submitting the file and handling rejections

SSA’s publication says to submit through BSO Electronic File Upload. You need a BSO account. SSA’s handbook notes that zipping the file can cut transmission time by as much as 80 percent. Our bulk W-2 upload guide covers file prep and SSA limits in more detail.

If SSA rejects the file

When a file has a backend error, SSA rejects it and issues a Resubmission Notice that explains the error. You have 45 days from the date of that notice to fix and upload the file. The publication adds these steps:

Log in to BSO and read the error information.
Correct the problem and retest the entire file.
Send the whole corrected file, not only the changed records.
Keep the original format, and enter the Resub Indicator and the WFID in the RA record.

The WFID is the identifier of the original submission, so keep it with the file from the first upload.

Federal acceptance is not state filing

SSA does not pass EFW2 state records on to state agencies. An accepted federal file does not mean your state filing is done. Check the separate process for each state where you withhold. Our W-2 e-file guide for payroll professionals walks through the federal and state sequence.

Common EFW2 problems and where to look

Symptom	Likely cause	Where to check
File rejected before processing	Wrong length record or non-ASCII character	Record length, encoding, hidden characters
Totals do not match payroll	Mapping used the wrong pay field	Field map and control totals
One employer total is off, grand total is right	Employee under the wrong RE block	Each RE-to-RT block
Money fields fail validation	Decimal point, minus sign or blanks in an amount	Money field rules above
Resubmission fails	Missing Resub Indicator or WFID in RA	RA record

Make these checks part of your payroll close rather than a February task. Errors found in January cost less than errors found after a Resubmission Notice.

Our perspective

We see the same pattern every filing season. The layout is rarely what trips teams up. The mapping is. A payroll export with a field called total pay looks complete, then Box 3 and Box 5 land wrong because nobody wrote down which source field feeds which box.

That is why we think a file format guide should end in a process, not a diagram. Write the mapping, run the file through AccuWage Online, reconcile each employer against the payroll register, and keep the control totals with the submission. Those four habits remove most of what causes a Resubmission Notice.

Our platform is built around that workflow. You can enter employee data, import it from Excel, and review it before anything is transmitted. W-2 and W-2c forms are filed with the Social Security Administration, and the format handling stays on our side. Pricing is per form with no subscription, so a small payroll team and a large one pay for what they file.

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If your team does not want to maintain an EFW2 export, our platform is IRS-authorized and handles the SSA submission for W-2 and W-2c forms. W-2 and ACA filing starts at $2.99 per form, with no subscription, signup fee or annual contract. You can import records from Excel, add optional state filing at $0.99 per form, send recipient copies by encrypted e-delivery at $0.19 per form, or use print and mail at $1.69 per form. See the full rate card on our pricing page, or start from the TaxFormHero home page.

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For a worked cost estimate at different headcounts, read our W-2 e-file cost breakdown. If you work with payroll exports from a specific provider, our guide for Paychex payroll data shows how the data maps across.

FAQ

What does EFW2 stand for?

SSA does not present it as an expanded phrase. It is the name of the agency’s electronic format for annual Form W-2 Copy A data. EFW2C is the matching name for Form W-2c Copy A data.

How long is an EFW2 record?

Every data record is 512 bytes, or 512 positions, in SSA’s 2026 publication. Fields are identified by position, so a record of any other length fails. Pad each field to its full length as the layout requires.

Which records are required in an EFW2 file?

RA, RE, RW, RT and RF are required. RA must be first, and RF must be last and appear once. RO, RS, RU and RV are optional.

Do I need AccuWage Online if my software builds the file?

SSA says to test application-created wage files in AccuWage Online to confirm they comply. Software developers are told the same. Running your own file through it before upload is the practical way to catch a problem before it becomes a rejection.

How long do I have to fix a rejected file?

SSA gives you 45 days from the date of the Resubmission Notice. Send the whole corrected and retested file in its original format, with the Resub Indicator and WFID in the RA record.