<prompt> Human: Ill be starting a new job on Monday and Id like to do a lump sum contribution to my 403b with some left over money in my savings. Since normally contributions would be payroll deductions before tax, how would I recover the tax I previously paid on this amount? I wouldnt want to pay taxes again when I withdraw down the line.  <response>: You cant do it directly. What you would need to do is up your 403b contributions from your paycheck, and live off the saved money, but youll still be limited to the yearly maximum contribution. 