The 401(k) contribution limit for a single person for tax year 2015 is $18,000 if the taxpayer is under the age of 50, according to the IRS. For taxpayers over 50, the IRS permits a special catch-up contribution of $6,000 in addition to the limit for those under 50.
The section of the internal revenue code that creates the 401(k) plan does not recognize marriage as a special status. All taxpayers are entitled to one 401(k) account regardless of their marital status. The annual contribution limits and catch-up contribution limits for 401(k) plans are subject to annual cost of living adjustments, which should be verified on an annual basis, explains the IRS.