401(k) Contribution Limits. As announced by the IRS, the contribution limit for 401(k) accounts will increase from $17,500 to $18,000 in 2015. Those 50 or older also get an increase, with the catch-up contribution increasing $500 from $5,500 to $6,000.he IRS recently released the new 2015 401k and IRA contribution and deduction limits. While 401k limits had remained flat since the last increase in 2012, they are going up again in 2015. 401k and catch-up contribution limits are all increasing. Limits for IRA contributions, however, are not going up.