In 2020, I participated as a W2 in my employer's 401k plan. As a 1099 contractor with a different company from Sep-Dec '20 contribute to my IRA and receive a tax benefit?

[MinhT1]

You are considered as covered by a retirement at work with your 401(k) plan.

As a covered individual, your eligibility to contribute to a deductible Traditional IRA depends on your filing status and your MAGI.

Please read this IRS document for more information.

[dmertz · Accepted solution]

In addition to being eligible to make a regular traditional IRA contribution (which may or may not be deductible depending on your MAGI and filing status), you also have the option to open and contribute to a SEP-IRA and take a self-employed retirement deduction.  TurboTax will automatically calculate the maximum permissible SEP contribution when you mark the Maximize box for a SEP contribution.  Reach this section under Business Items -> Business Deductions and Credits.