If your intent is to maximize your deductible individual 401(k) contributions, leave the dollar boxes blank and mark the Maximize box, then refer to the Keogh, SEP and SIMPLE Contributions Worksheet for your allowable contributions. Your maximum regular elective deferral of $20,500 will be on line 9, the maximum catch-up elective deferral of $6,500 will be on line 17 and, assuming sufficient net profit (something on the order of $215,000 or more), your allowable employer contribution of $40,500 will be on line 13.
If you enter dollar values yourself and do not mark the maximize box, your regular elective deferral (or Roth contribution) is not permitted to exceed $20,500, your catch-up contribution is not permitted to exceed $6,500 and your employer contribution is not permitted to exceed on line 5 of the Keogh, SEP and SIMPLE Contribution Worksheet, with the total of the three not to exceed $67,500.
