FSA vs HSA: Pick Right at Open Enrollment

Open enrollment is the one week a year when a guessing error locks in for twelve months, and no account punishes a guess like the flexible spending account. Elect too much and the surplus vanishes. Elect too little and you pay for care with after-tax dollars you could have sheltered. With fall open enrollment season here, I sat down with the Internal Revenue Service limits for 2026 and worked the actual decision, because the right answer is arithmetic, not vibes.

The 2026 limits, side by side

For 2026, a health savings account allows $4,400 for individual coverage and $8,750 for family coverage, plus a $1,000 catch-up at age 55 and older, according to the IRS limits summarized by Voya. The health FSA caps employee contributions at $3,400 under IRS Revenue Procedure 2025-32, as summarized by GoodRx, and the most you can carry over, if your plan allows carryover at all, is $680. The dependent care FSA limit rises to $7,500 for most filers in 2026. Qualifying for an HSA requires a high-deductible health plan, with a minimum deductible of $1,700 individual or $3,400 family for 2026. That eligibility line, not preference, is the first fork in the decision.

Figure 1: 2026 contribution limits for health accounts. Source: IRS Revenue Procedure 2025-32 and IRS 2026 HSA limits, via Voya and GoodRx summaries, October 2026.

The only FSA question that matters: what will you surely spend?

An FSA dollar is pre-tax, which is the whole appeal. Money routed through the account skips federal income tax and payroll tax, so at a combined marginal rate around 30 percent, $3,400 of election saves roughly $1,000 against paying the same bills from take-home pay. But the carryover cap turns over-election into a donation: anything above $680 left unspent at year end, in a plan with carryover, is forfeited, and plans with a grace period have their own deadlines. My rule is to elect only the expenses I can name in October: the recurring prescriptions, the planned dental crown, the contact lens order, the therapy copays already on the calendar. Named expenses only. The year I elected for a hypothetical orthodontics consult that never happened taught me this rule at retail price.

Why the HSA wins for anyone who can leave it alone

The HSA has no use-it-or-lose-it clock. Balances roll over in full, the account is yours when you change jobs, and contributions, growth, and withdrawals for qualified care all stay tax-free. That triple treatment is why I treat the HSA as a retirement account wearing a health costume: pay routine care from cash flow when you can afford to, let the HSA compound, and keep the receipts. The constraint is honesty about the deductible. A family that elects the high-deductible plan for the HSA but cannot comfortably cover the $3,400 family minimum deductible, let alone a bad year, has bought a tax benefit with anxiety. Run your worst realistic year, not your best one, before choosing.

The dependent care trap hiding in the same form

The dependent care FSA, $7,500 for most filers in 2026, looks like free money for households paying for childcare, and it can be. But it reimburses after you pay and document the expense, it is also use-it-or-lose-it, and it interacts with the child and dependent care tax credit, so the same dollars cannot do both jobs. Households should compare the two before electing, ideally with last year's actual childcare invoices in hand rather than a hopeful estimate. Childcare that changes mid-year, a nanny who quits, a preschool switch, is the classic way this account strands money.

My open enrollment checklist

One, confirm which health plan you are actually electing and whether it is HSA-qualified. Two, list named, dated medical expenses for next year and set the FSA at that total, not a round number that feels safe. Three, if you have an HSA, decide whether you are spending from it or investing it, and set the election to match that decision. Four, check whether your FSA offers the $680 carryover or a grace period, because the spending deadline differs. Five, screenshot your elections before the window closes. Benefits portals are unforgiving in January, and the screenshot is the only evidence that helps.

FAQ

What are the HSA limits for 2026? $4,400 for individual coverage and $8,750 for family coverage, plus a $1,000 catch-up contribution at age 55 and older, per the IRS limits summarized by Voya.

What is the health FSA limit for 2026? $3,400 in employee contributions under IRS Revenue Procedure 2025-32. If your plan offers carryover, at most $680 can roll into the next year.

Who qualifies for an HSA? You must be enrolled in a high-deductible health plan, which for 2026 means a deductible of at least $1,700 for individual coverage or $3,400 for family coverage, and you generally cannot be enrolled in Medicare.

What is the dependent care FSA limit for 2026? $7,500 for most tax filers. It is use-it-or-lose-it and reimburses documented dependent care expenses you have already paid.

Should I max the FSA to save the most tax? Only up to expenses you are confident you will incur. Unspent amounts above the $680 carryover maximum are forfeited, which can erase the tax saving entirely.