Open enrollment season is here, and millions of Americans are staring at the same confusing choice: a flexible spending account or a health savings account.
The two sound nearly identical, but they follow completely different rules, and picking wrong can cost you hundreds of dollars a year.
The biggest difference comes down to who controls the money.
That single distinction drives almost everything else, from rollover rules to what happens when you change jobs.
With an FSA, you decide during open enrollment how much to set aside for the year, and that money typically must be spent by December 31.
Some employers offer a grace period or let you roll over a small amount, but there's no guarantee.
Use-it-or-lose-it is the default, and any leftover cash generally goes back to your employer.
An HSA works more like a bank account you own.
It's only available if you're enrolled in a high-deductible health plan, but the money never expires.
You can invest it, let it grow tax-free, and keep it even if you switch jobs or retire.
After age 65, you can spend it on almost anything without a penalty, though non-medical withdrawals get taxed like regular income.
Both accounts let you pay for qualified medical costs with pre-tax dollars, which is where the real savings live.
If you're in the 22% federal tax bracket, putting $1,000 into either account saves you roughly $220 in federal taxes, plus state taxes in most states.
That's an instant return no savings account can match.
The catch is that you have to actually use the money on eligible expenses.
Doctor visits, prescriptions, dental work, glasses, and many over-the-counter items count.
So do some less obvious costs, like menstrual products, sunscreen, and certain home medical equipment.
Contribution limits for 2025 sit at $3,300 for individual FSAs and $4,300 for HSAs, with higher caps for family coverage.
HSAs also let you contribute an extra $1,000 if you're 55 or older.
Here's where people get tripped up: you can't have both.
IRS rules block you from opening an HSA if you're covered by a general-purpose FSA, yours or your spouse's.
A limited-purpose FSA for dental and vision only is the exception.
If your employer offers a generous HSA match, that's free money and usually the smarter play.
If you know you'll have predictable expenses like a recurring prescription or planned surgery, an FSA can work well because the full amount is available on day one, not just what you've deposited so far.
The worst outcome is guessing wrong on your FSA amount and watching funds vanish in January.
Undershooting costs you the tax break; overshooting costs you the cash itself.
Our take: if you qualify for an HSA, treat it like a long-term retirement tool and pay small medical bills out of pocket when you can.
If you're stuck with an FSA, estimate conservatively and spend deliberately before the deadline.
Final Thoughts
Either way, don't let this money slip through your fingers.