Retirement tax questions

Thanks for this informative reply. I have a further clarifying question which you perhaps can help with: what about the EMPLOYEE contribution to a 401(k)? My partner wants to set up payroll deductions to her plan but we always extend our taxes. Can she count her contributions between April and October toward the prior year's limit? If not, of course, she'll want to contribute more each paycheck. Thanks for any info you can provide.