Instructions for Form CT-1 - Introductory Material

Future Developments

For the latest information about developments related to Form CT-1 and its instructions, such as legislation enacted after they were published, go to

What's New

Changes to tax rates and compensation bases.   For the 2014 tax rates and compensation bases, see Employer and Employee Taxes, later.


Tier 1 Employee Additional Medicare Tax withholding.   In addition to withholding Tier 1 Employee Medicare tax at 1.45%, you must withhold a 0.9% Tier 1 Employee Additional Medicare Tax from compensation you pay to an employee in excess of $200,000 in a calendar year. You are required to begin withholding Tier 1 Employee Additional Medicare Tax in the pay period in which you pay compensation in excess of $200,000 to an employee and continue to withhold it each pay period until the end of the calendar year. Tier 1 Employee Additional Medicare Tax is only imposed on the employee. There is no employer share of Tier 1 Additional Medicare Tax. All compensation that is subject to Tier 1 Medicare tax is subject to Tier 1 Employee Additional Medicare Tax withholding if paid in excess of the $200,000 withholding threshold.

  Visit and enter “Additional Medicare Tax” in the search box for more information on Tier 1 Employee Additional Medicare Tax.

Change of address.   Use Form 8822-B, Change of Address or Responsible Party—Business, to notify the IRS of an address change.

Correcting a previously filed Form CT-1.   If you discover an error on a previously filed Form CT-1, make the correction using Form CT-1 X, Adjusted Employer's Annual Railroad Retirement Tax Return or Claim for Refund. Form CT-1 X is filed separately from Form CT-1. For more information, see the Instructions for Form CT-1 X or visit and enter “correcting employment taxes” in the search box.

Federal tax deposits must be made by electronic funds transfer (EFT).   You must use EFT to make all federal tax deposits. Generally, an EFT is made using the Electronic Federal Tax Payment System (EFTPS). If you do not want to use EFTPS, you can arrange for your tax professional, financial institution, payroll service, or other trusted third party to make electronic deposits on your behalf. Also, you may arrange for your financial institution to initiate a same-day wire payment on your behalf. EFTPS is a free service provided by the Department of Treasury. Services provided by your tax professional, financial institution, payroll service, or other third party may have a fee.

  To get more information about EFTPS or to enroll in EFTPS, visit the EFTPS website at, or call 1-800-555-4477 or 1-800-733-4829 (TDD). Additional information about EFTPS is also available in Pub. 966, Electronic Federal Tax Payment System: A Guide To Getting Started.

Outsourcing payroll duties.   Employers are responsible to ensure that tax returns are filed and deposits and payments are made, even if the employer contracts with a third party to perform these acts. The employer remains responsible if the third party fails to perform any required action. If you choose to outsource any of your payroll and related tax duties (that is, withholding, reporting, and paying over taxes imposed by the Railroad Retirement Tax Act, FUTA, and income taxes) to a third-party payer, such as a payroll service provider or reporting agent, visit and enter “outsourcing payroll duties” in the search box for helpful information on this topic.

Paid preparers must sign Form CT-1.   Paid preparers must complete and sign the paid preparer's section of Form CT-1.

Where can you get telephone help?   You can call the IRS Business and Specialty Tax Line at 1-800-829-4933 or 1-800-829-4059 (TDD/TTY for persons who are deaf, hard of hearing, or have a speech disability) Monday–Friday from 7:00 a.m.–7:00 p.m. local time (Alaska and Hawaii follow Pacific time) for answers to your questions about completing Form CT-1 or tax deposit rules.

Additional information.   
  • Pub. 15 (Circular E), Employer's Tax Guide, contains information for withholding, depositing, reporting, and paying over employment taxes.

  • Pub. 15-A, Employer's Supplemental Tax Guide, contains specialized and detailed employment tax information supplementing the basic information provided in Pub. 15 (Circular E).

  • Pub. 15-B, Employer's Tax Guide to Fringe Benefits, contains information about the employment tax treatment of various types of noncash compensation.

  • Pub. 915, Social Security and Equivalent Railroad Retirement Benefits, contains the federal income tax rules for social security benefits and equivalent Tier 1 railroad retirement benefits.

  • The Railroad Retirement Board (RRB) website at contains additional employer reporting information and instructions.

  You can order forms and publications by visiting or calling 1-800-TAX-FORM (1-800-829-3676).

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