Open enrollment season is here, and millions of Americans are staring at a benefits form with two confusing acronyms: FSA and HSA.
Pick wrong, and you could leave hundreds of dollars on the table — or worse, forfeit money you never get back.
Both accounts let you pay for medical costs with pre-tax dollars.
But they follow completely different rules, and the gap matters more than most people realize.
An FSA, or flexible spending account, is offered by many employers.
You decide how much to set aside, and the money comes out of your paycheck before taxes.
The catch: in most cases, you have to use it by the end of the plan year or lose it.
Some employers offer a grace period or let you roll over a small amount — often around $640 — but the rest vanishes.
An HSA, or health savings account, only works if you're enrolled in a high-deductible health plan.
Here's where it gets interesting: the money is yours forever.
You can invest it, let it grow, and spend it decades later — even in retirement.
For 2025, you can contribute up to $4,300 for individual coverage or $8,550 for family coverage to an HSA.
Those limits typically rise each year with inflation.
FSA limits are usually lower and set by your employer within IRS caps.
The tax treatment is where the HSA pulls ahead.
Contributions go in pre-tax, growth is tax-free, and withdrawals for qualified medical expenses stay tax-free.
That's a rare triple advantage in the tax code.
If your employer doesn't offer a high-deductible plan, or you have predictable expenses like glasses, dental work, or regular prescriptions, an FSA can still shave real money off your bill.
And some employers contribute to your FSA too.
There's one more wrinkle: you can't have both unless you're in a very specific situation.
And once you enroll in Medicare, you can no longer contribute to an HSA.
The smart move for most people with a high-deductible plan is to fund the HSA, pay smaller medical bills out of pocket when possible, and let the account grow.
Treat it like a retirement account that happens to cover doctor visits.
If you're stuck with an FSA, estimate your expenses carefully.
Underfunding wastes the tax break; overfunding wastes your own money.
Dig out last year's receipts before you decide.
The bottom line: an HSA rewards patience and long-term thinking.
An FSA rewards people who know exactly what they'll spend.
Run the numbers against your actual medical history, not your hopes.
Your benefits portal won't warn you if you pick the wrong one.
Final Thoughts
It'll just quietly take your money and move on.