HSA basics
Health Savings Account. Available only with a High Deductible Health Plan (HDHP). Annual limits set by the IRS. Funds roll over year to year, and the account is yours for life. Can be invested once balance hits a plan threshold.
FSA basics
Flexible Spending Account. Available with most employer health plans. Annual limit set by the IRS, lower than HSA. Use-it-or-lose-it: any unspent funds at year-end are forfeited (with a small carryover or grace period in some plans).
Tax treatment
Both reduce federal income tax wages, FICA wages, and most state income tax wages when contributed through a Section 125 cafeteria plan via payroll deduction.
Triple tax advantage of HSA
HSA is the only account in the US tax code that is tax-free at all three stages: contribution, growth, and qualified withdrawal. No other vehicle matches this.
Limited Purpose FSA
A special FSA limited to dental and vision expenses. Can co-exist with HSA. Useful if you want HSA contributions plus dental/vision FSA.
Dependent Care FSA
Different account for dependent care expenses (childcare, after-school care). Separate annual limit. Use-it-or-lose-it.