Can I contribute to a IRA if I did not max out my 401 due to retirement?

[MinhT1]

It depends.

If you are covered by a retirement plan at work (whether you max out your contributions to your 401(k) or not), your deductible IRA contribution may be reduced or eliminated depending on your filing status and Modified AGI.

Please read this IRS document for more information.

[Opus 17]

The contribution limits are separate, because IRAs and workplace plans are covered by different laws.  Whether you max out your 401k or not, you can still max out your IRA if you prefer.  However, you must use the eligibility rules for "covered" by a plan if you participate in the plan in any way, even at less than the maximum.

You can always contribute to a traditional IRA, no matter what your income.   You may not be able to deduct the contributions.  Making non-deductible contributions to a traditional IRA add some complexity to your taxes later in life.  You may also be able to contribute to a Roth IRA, depending on the income and other limits.