Where do I enter my 401(k) or Thrift Savings Plan (TSP) contribution and deduction?

If you have a 401(k) or TSP through your employer, your contribution is reported in Box 12 of your W-2 with the letter code D. TurboTax will handle the tax deduction for you.

Don’t re-enter your contribution in the retirement section, because it's already in your W-2.

Individual 401(k) plans for the self-employed (also called solo 401(k) or solo-K plans) are entered in the Other Business Situations section of Income & Expenses in TurboTax.