Colorado W2 E-File Requirements & EFW2 Text Format | CO Revenue Online

Colorado W2 Electronic Filing Common Questions and Answers

Does Colorado mandate filing W-2s electronically?

As a Colorado employer you are only required to file electronically when you have 250 or more W2 forms. You will need to check with the state annually, since this threshold is subject to change.

What is the name of the publication that defines Colorado W2 E-Filing format and details?

Refer to "Withholding 6: Methods of Filing Colorado Annual W-2 Tax Data".

What software can I use to generate Colorado W2 E-File submissions?

You can use our W2 Mate software to create W2 E-File submissions that comply with Colorado requirements. To learn more about W2 Mate and download a demo you can visit


Can I mail my W2 E-File submission on a CD or other formats of magnetic media to Colorado?

Colorado no longer accepts magnetic media submissions by " inch tape, 3480 cartridge, CD-ROM, diskette or by email submissions.

Does Colorado Follow the EFW2 format defined by the SSA?

Yes Colorado follows the "Specifications for Filing Forms W-2 (EFW2)" as defined by the SSA, but the state also has its own special requirements.

How Can I submit the CDOR-EFW2 (W2 E-File) Withholding file attachment to Colorado?

You will need to register as "Withholding Submitter " in Revenue Online (www.Colorado.gov/RevenueOnline ) and then under "Additional Services" click on the link "Submit Year-End Withholding". Then, choose "Submit a Withholding File Attachment."

Do you need to include the RV (State Total) record as part of the Colorado W2 E-File Submission?

The RV record is not utilized by Department of Revenue and should be excluded from the submission.

Do you need to include the RS (State Wage) records as part of the Colorado W2 E-File Submission?

Yes this record is mandatory and has to be included.

Does Colorado have a special file naming convention for W2 E-File submissions?

No, the state does not have any special requirements; however it's a good idea to have the company name included in the file name and to have .txt as the file extension.

Is the Colorado W2 Electronic Filing submission attachment an ASCII text file?

Yes the submission is a text file that follows the specifications of both the SSA EFW2 format and the Colorado requirements defined by "Withholding 6: Methods of Filing Colorado Annual W-2 Tax Data".

Does Colorado have any requirements for money fields?

Money fields must contain only numbers. No punctuation. Include both dollars and cents with the decimal point assumed (example: $89.70 = 000008970). All state withholding shall be rounded to the nearest dollar. Right-justify and zero fill to the left. Any money field that has no amount to be reported must be filled with zeros, not blanks. Colorado withholding cannot be greater than Colorado taxable wages.

Does Colorado have any requirements for Social Security Number (SSN)?

Use the number shown on the original/replacement SSN card. Omit hyphens. SSNs may NOT begin with a 666 or 9. If there is no SSN available for the employee, enter zeros (0) in positions 10 - 18 of the RS Record, and submit paper W-2 statements for these employees. Do NOT enter a fictitious SSN (for example, 111111111, 333333333 or 123456789).

How do I know if my submission was successful?

After a successful submission to Colorado, "Revenue Online" website will automatically populate the webpage with a confirmation. It's very important that you print this page for your records.

How do I contact Colorado with questions about my W2 E-File submission?

Call (303) 205-8292, Monday through Friday, 8 a.m. to 5 p.m.

The electronic filing engine available inside our W2 Mate® software gives Colorado employers and tax professionals the ability to e-File W2s with both the state of Colorado and the Social Security Administration’s (SSA). To learn more about W2 Mate visit https://www.realtaxtools.com/W2-Mate.html , email sales@realtaxtools.com or call 1-800-507-1992. 

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