401K & IRA contribution. Can I contribute to traditional IRA to help reduce tax payment? I already contributed to 401K @ work, but not to the max limit for the year.

You can contribute to a Traditional IRA, as long as you have earned income and you are under the age of 70 and 1/2. For a Traditional IRA contribution, once you reach the year in which you turn age 70 ½ you are no longer eligible to make a contribution. 

For any Traditional IRA deduction, to reduce your tax liability it depends on your filing status, your income, and if you or your spouse is covered by a retirement plan with your Employer (in your case you are covered by an employer). If you do, there are a couple of possibilities. If you (and a jointly-filing spouse) didn’t contribute to an employer-sponsored retirement plan, like a 401 (k), or self-employed retirement plan your entire Traditional IRA contribution is deductible.

But if you (and/or your jointly-filing spouse) contributed to an employer-sponsored or self-employed retirement plan in 2017, the amount you can deduct will depend on your tax filing status and modified adjusted gross income (MAGI).

Note that if your MAGI is:

• Below the phase-out range—your entire contribution is deductible.
• Above the phase-out range—you can’t deduct anything.
• Within the phase-out range—you can make a partial deduction (we’ll calculate this for you).

Here are the MAGI phase-out ranges for tax year 2017 if you participated in another retirement plan:

• Single, Head of Household, or Married Filing Separately, the phase-out range is $62,000 – $72,000
• Married Filing Jointly or Qualified Widower, the phase-out range is $99,000 – $119,000
• Married Filing Separately (but lived with your spouse), the phase-out range is $0 – $9,999

If you didn't participate in another retirement plan, but your spouse did, and you're:

• Filing jointly, the phase-out range is $186,000 – $196,000
• Filing separately, the phase-out range is $0 – $9,999

The most you can contribute to all of your Traditional IRA is the smaller of: 

• $5,500 ( $6,500 if you're age 50 or older by the end of the year) or
• your taxable compensation for the year. 

The deadline to make 2017 IRA contributions is until April 17, 2018.