Excess Social Security and Tier 1 RRTA Tax Withheld

by | Jun 17, 2026 | Individual Tax

Concise Takeaway

When a taxpayer has too much Social Security or Tier 1 RRTA tax withheld, the excess is refundable. The refund process depends on whether the taxpayer had multiple employers or one employer who withheld too much.

When Excess Withholding Occurs

Most employers must withhold Social Security tax from wages. Railroad employers must withhold:

  • Tier 1 RRTA tax (equivalent to Social Security + Medicare)
  • Tier 2 RRTA tax (railroad pension component)

Excess withholding can occur when:

  • A taxpayer works for two or more employers and total wages exceed the Social Security wage base
  • A taxpayer works for multiple railroad employers and compensation exceeds the Tier 2 RRTA wage base

When this happens, the combined withholding may be more than the maximum allowed for the year.

From the document: “A taxpayer that had more than one employer during the taxable year and whose total wages and compensation were over the annual Social Security wage base limit… may have exceeded the maximum amount due for the tax year.”

How to Claim a Refund

Excess Social Security or Tier 1 RRTA (multiple employers)

Taxpayers claim the excess on their income tax return using Schedule 3.

“A taxpayer can receive a refund for the excess Social Security and Tier 1 RRTA tax withheld by filing Schedule 3 with their tax return.”

Excess Tier 2 RRTA (multiple railroad employers)

Taxpayers must file Form 843 to request a refund.

Joint Returns

Each spouse must calculate excess withholding separately.

Employer Error Rules

If one employer withheld too much:

  • The taxpayer cannot claim the excess on their tax return
  • The employer must correct the error
  • If the employer refuses or cannot correct it, the taxpayer may file Form 843

“A taxpayer who had one employer that withheld too much… can not claim the excess on their tax return. The employer should adjust the excess.”

Medicare Withholding Reminder

All wages are subject to Medicare tax. There is no wage base limit, so Medicare withholding cannot be “excess” in the same way Social Security can.

Excess Withholding Flow Summary

  1. Determine whether withholding exceeded the annual wage base
  2. Identify whether the taxpayer had one or multiple employers
  3. Use Schedule 3 for excess Social Security or Tier 1 RRTA
  4. Use Form 843 for excess Tier 2 RRTA or employer errors
  5. Calculate separately for each spouse on joint returns