Contributions you make to your 401(k) plan can reduce your tax liability at the end of the year as well as your tax withholding each pay period. However, you do not actually take a tax deduction on your income tax return for your 401(k) plan contributions.
Contributions you make to a traditional IRA may be fully or partially deductible, depending on your circumstances.
Generally, amounts in your traditional IRA (including earnings and gains) are not taxed until distributed.
You cannot deduct contributions to a Roth IRA. The same combined contribution limit applies to all of your Roth and traditional IRAs.