The 401k at my company is not the best, but not the worst either. I started by contributing 6% as the company matches 50% of the first 6%. I did this for a few years, until I got serious about retirement investing (after reading this blog). Now I am up to an 18% contribution, but I wonder how to make sure I get the max $18,000 dollars per year. Since I get paid overtime and a (small) year end bonus, if I just set the percentage to equal $18,000 based on my base salary, it will likely go over the contribution by the end of the year. My strategy thus far has been to aim to get about $15,000 contributed by year end. Is there a better way to max your 401k? There is no option to put in a dollar amount and I can only change my contribution twice per year during open enrollment.