<prompt> Human: Hi, if I were to fund 3,400 into my HSA for the remainder of the year VIA employer sep - dec 2017, would my tax savings be the same as if I funded it from the beginning of the year jan - dec 2017? Will all the payroll tax benefits net itself out in the end or did I leave money on the table by doing it last minute? Thank you in advanced.  <response>: Contributing in one lump sum vs spread throughout the year does not change the amount of taxes saved. You did not leave money on the table. However, contributing with after tax dollars and then deducting it from gross income at tax time will save you less than if you contribute through payroll deductions. With payroll deductions, you also get the FICA taxes off, which you cant get back if you contribute after-tax. It sounds like you land in the former group, as you mention you are doing it via employer 