The maximum amount an employee can contribute to a 401(k) plan is determined annually. You may be allowed catch up contributions in addition to annual limit, if you are age 50 or older. Refer to “Elective Deferrals” in Publication 525,taxable and Nontaxable Income. The maximum amount applies to an employee’s aggregate pre-tax contributions to a 401(k) plan and 403(b) plan. There are several different limits that apply to a 401(k) plan in addition to the overall contribution limit. These limits, your salary, and the type of 401(k) plan to which you are contributing may limit your 401(k) contributions to a lesser amount.
The rules for retirement plans are complex. Your plan administrator should have written information about your particular plan that explains these limitations as well as other regulations that apply.
Click here for more information and Contribution Limits.