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Paper Trails > Common W-2 Mistakes to Avoid

Common W-2 Mistakes to Avoid

The most common W-2 mistakes are incorrect employee names and Social Security numbers, wrong employer information, excess benefit contributions, and missing the January 31 deadline. Each error carries a per-form penalty, and with employees numbering in the dozens, a single mistake repeated across a payroll adds up quickly.

Most of these are caught in December if anyone looks. Here's what goes wrong, what it costs, and how to fix a W-2 that's already gone out.

 

Key Takeaways from this Article

  • Employee names and Social Security numbers have to match the Social Security card exactly, hyphens included.
  • W-2s are due to employees and to the SSA by January 31, the same date for both.
  • If you file 10 or more information returns in a year, you're required to e-file. Paper filing when you should have e-filed is itself a penalty.
  • Penalties are charged per form and rise the longer an error goes uncorrected.
  • Filing and furnishing are separate obligations, so one W-2 that's both late to the SSA and late to the employee can draw two penalties.

 

What Are the Most Common W-2 Mistakes?

Five come up more than the rest:

  • Incorrect employee data, especially names and Social Security numbers
  • Incorrect employer data such as address or EIN
  • Over-contributions to retirement accounts or HSAs
  • Paper filing when e-filing is required
  • Missing the January 31 deadline

 

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Incorrect Employee Data

The name and Social Security number on a W-2 must match the employee's Social Security card exactly. Not approximately. If the card shows a hyphenated surname and your W-2 doesn't, that's an error the SSA will flag.

December is the time to verify this, not January. Send each employee their own details and ask them to confirm against their card rather than from memory. Newly married employees who changed their name socially but not with the Social Security Administration are a common source of mismatches.

 

Incorrect Employer Data

Your company name, address, and federal EIN have to be right and consistent across every form you file. The IRS tracks your filings by EIN, so a wrong digit there doesn't just create one bad W-2, it disconnects the whole batch from your account.

Worth checking if you've moved, changed your legal name, or restructured during the year.

 

Over-Contributions

Retirement plans and HSAs have annual contribution limits, and payroll doesn't always stop at them, particularly for employees who changed jobs mid-year and contributed elsewhere first.

For a 401(k) or 403(b) over-contribution, the employee contacts the plan administrator for a corrective distribution. For excess HSA contributions you have two options: request the excess back from the financial institution and refund the employee, then issue a Form W-2c showing the reduced Box 12 amount, or leave it and report the excess as taxable wages.

 

Filing on Paper When You Shouldn't

If you file 10 or more information returns of any kind in a year, counting W-2s, 1099s, and others together, you're required to file electronically. That threshold dropped sharply a couple of years ago and it catches employers who have always filed on paper.

Paper filing when you were required to e-file is a penalty on its own, assessed per form. Most businesses with more than a handful of employees are over the line.

 

Filing Late

W-2s go to employees and to the Social Security Administration by January 31. One date, both obligations. If January 31 falls on a weekend the deadline moves to the next business day.

You also file Form W-3 with the SSA alongside the W-2s when filing on paper. E-filers don't submit a separate W-3.

 

What Do W-2 Errors Cost?

Penalties are per form and escalate with time. These are the amounts for returns due in 2026, and they're adjusted for inflation every year.

When you file or correct Per form Annual cap, small business
Within 30 days of the deadline $60 $239,000
After 30 days, through August 1 $130 $683,000
After August 1, or never filed $340 $1,366,000
Intentional disregard $680 minimum No cap

 

Two things about how these stack. Filing a return with the SSA and furnishing a copy to the employee are separate requirements under separate sections of the code, so a W-2 that's late on both counts can generate two penalties rather than one. And the per-form structure means an error in your payroll setup that repeats across forty employees is forty penalties.

The upside of the tiered structure is that speed genuinely pays. Catching something in February costs $60 a form. The same error found in September costs $340.

 

How Do You Correct a W-2?

Use Form W-2c, Corrected Wage and Tax Statement, for anything already filed with the SSA. You send the corrected form to the SSA and a copy to the employee.

If you catch the error before filing, you don't need a W-2c at all. Just correct it and file the right version. This is the entire argument for reviewing W-2s in the last week of December rather than treating January 31 as the first checkpoint.

A W-2c is also what you use when an employee's name or Social Security number was wrong, even if every dollar figure was right.

 

FAQs: W-2 Mistakes and Deadlines

  • January 31, for both giving W-2s to employees and filing them with the Social Security Administration. If that date falls on a weekend, the deadline moves to the next business day. There's no separate, later deadline for the SSA copy the way there used to be years ago.

  • Through the isolved People Cloud employee self-service portal, using the login your employer issued. Former employees generally keep access to prior-year W-2s in the portal after leaving. If you can't get in or never set up a password, our isolved login help page has the portal link and reset steps, or your former employer's payroll contact can help.

  • For returns due in 2026: $60 per form if corrected within 30 days, $130 if corrected by August 1, and $340 after that or if never filed. Intentional disregard starts at $680 per form with no annual cap. Annual maximums apply to the first three tiers and are lower for small businesses. The amounts are adjusted for inflation each year.

  • File Form W-2c, Corrected Wage and Tax Statement, with the SSA and give a copy to the employee. You need a W-2c for any error on a form already filed, including a misspelled name or wrong Social Security number, not just wrong dollar amounts. If you catch the mistake before filing, correct the original instead.

  • Yes, if you file 10 or more information returns in a year. That count combines all types together, so W-2s plus 1099s plus anything else. The threshold used to be much higher and dropped sharply, which caught a lot of small employers who had always filed paper. Filing on paper when you were required to e-file carries its own penalty.

  • Not for filing your return. A final pay stub shows gross wages, while Box 1 of a W-2 shows taxable wages after pre-tax deductions, so the two usually don't match. The stub is useful for an early estimate of what you'll owe or get back, but file from the W-2.

 

Catch It in December

Almost every W-2 problem is cheaper to fix before the form is filed than after. A name mismatch found on December 20 is a data entry change. The same mismatch found in March is a W-2c, an amended filing, and a confused employee whose tax return got rejected.

Paper Trails clients get their W-2 packets at the start of January, and employees can pull their own copies from the isolved portal. Before that, we run year-end verification so the data problems surface while they're still free to fix. If you want to see what payroll and tax services cost, it's all on the pricing page.

 

Updated: September 2026

Written by: Jon Portanova

 

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