The max contribution you can make to your 401k in 2013 is $17,500. Your employer matches are not counted against this amount, so depending on your company’s match policy you could exceed this. Separately, the max contribution you can make to your Individual Retirement Account (IRA) is $5,500. It is important to note these two tax deferred accounts are mutually exclusive, so you could directly invest $23,000 in any one year.
If you are 50 years of age or older, you can invest $1,000 more into your IRA, to $6,500 total, plus an additional $5,500 for a total of $23,000 into your 401k. This would make a grand total of $29,500 in any given tax year.
For more information, the IRS 401k Frequently Asked Questions page can be found here.