Both HSAs and FSAs allow you to pay for qualified medical expenses with pre-tax dollars. One key difference, however, is that HSA balances can roll over from year to year, while FSA money left unspent at the end of the year is forfeited.

If you have both an HSA and an FSA, you must pay certain expenses, such as those that apply to the HDHP deductible, out of your HSA before you may use your limited-purpose FSA.

Check out our Terminology and Definition section for more details.