How is income reported if an employer prior to 2018 reports wages prior to 2018 on a 2018 W-2?

[rjs]

The simplest thing to do is report your wages the way that your employer reported them. Just enter the W-2 as it is. Note that wages are supposed to be reported in the year that they are paid to you, which might be after the year in which you did the work. If you were paid in 2018 for work that you did in 2017 (or an earlier year), that payment is supposed to be included in your 2018 W-2 and reported on your 2018 tax return.

If your W-2 is incorrect, and reporting it as-is creates a significant problem for you, you have to ask the employer to issue a corrected W-2. See the following link on the IRS web site to get an idea of what the next steps will be if the employer refuses to send a corrected W-2. If you end up needing to file Form 4852, TurboTax will prepare it for you and include it in your tax return. But the first step is to contact the employer.

https://www.irs.gov/faqs/irs-procedures/w-2-additional-incorrect-lost-non-receipt-omitted/w-2-additi...

[WillK]

If there are wages that were paid to you in any other year besides 2018 on your 2018 W-2, you need to ask your employer to correct the W-2. Only wages paid to you in 2018 should be on your W-2 for 2018. If you have back wages paid to you in 2018, they should be reported on your W-2 for 2018, and you need to claim them as wages for 2018.