Health savings accounts and flexible spending accounts get lumped together because both let you pay medical bills with money that never gets taxed. That is where the similarity stops. They have different owners, different eligibility rules, different contribution ceilings, and completely different answers to the only question most people actually care about, which is what happens to the money you do not spend.
Every figure below comes from the IRS revenue procedures and publications that set these numbers, checked on September 5, 2026. Limits change annually, so the tax year attached to a number matters more than the number itself. This is a plain-English summary of published rules, not tax advice for your return.
What an HSA Is and Who Can Open One
A health savings account is a bank or brokerage account in your own name. You fund it, you own it, and Publication 969 states plainly that an HSA is portable: it stays with you if you change employers or leave the work force entirely.
The catch is on the front end. To contribute for a given month you have to be covered on the first day of that month by a qualifying high deductible health plan, have no other disqualifying health coverage, not be enrolled in Medicare, and not be claimable as a dependent on someone else’s return. Eligibility is tested month by month, so a gap in coverage is a gap in contributions.
For 2026, Revenue Procedure 2025-19 defines a qualifying plan as one with an annual deductible of at least $1,700 for self-only coverage or $3,400 for family coverage, with out-of-pocket maximums no higher than $8,500 and $17,000. For 2027, Revenue Procedure 2026-24 moves those to $1,750 and $3,500 in deductible and $8,700 and $17,400 in out-of-pocket maximums.
Two 2026 changes widened the door. Section 71307 of Public Law 119-21 made bronze and catastrophic marketplace plans available as individual coverage through an Exchange count as high deductible health plans for months beginning after December 31, 2025, even when they miss the normal deductible and out-of-pocket tests. IRS Notice 2026-5 confirms that and adds that an otherwise identical plan bought off-Exchange also qualifies. Separately, a direct primary care arrangement costing no more than $150 a month for one person or $300 for more than one no longer breaks eligibility. If you were shut out of an HSA before, re-check.
If you do not have qualifying coverage at all, read can you have an HSA without insurance first, because the answer to contributing and the answer to spending are different.
What a Health FSA Is and Who Can Open One
A health flexible spending arrangement is not an account you open. It is a benefit your employer offers inside a cafeteria plan, funded by a salary reduction you elect before the plan year starts. Publication 969 is blunt about the boundary: self-employed people are not eligible for FSAs. No employer, no FSA.
You pick your annual number once, during open enrollment, and you generally cannot change it mid-year unless a specific life event lets you. Money comes out of each paycheck.
The FSA’s one genuine structural advantage is front-loading. Publication 969 says you must be able to receive the maximum amount of reimbursement, meaning your full annual election, at any time during the coverage period, no matter how little has actually been withheld so far. Elect $3,000 in January, need $3,000 of dental work in February, and the plan pays it even though $250 has been deducted. An HSA cannot do that. An HSA only holds what you have already deposited.
HSA vs FSA Side by Side
| Health Savings Account (HSA) | Health FSA | |
|---|---|---|
| 2026 contribution limit | $4,400 self-only, $8,750 family | $3,400 in salary reductions, per employer |
| 2027 contribution limit | $4,500 self-only, $9,000 family | Not published as of Sept 5, 2026 |
| Age 55+ catch-up | Extra $1,000 | None |
| Who can have one | Anyone with an HSA-qualified HDHP and no disqualifying coverage | Employees only, if the employer offers it |
| Who owns the money | You | The employer’s plan |
| Unused money at year end | Rolls over indefinitely | Forfeited, except a carryover up to $680 or a grace period up to 2.5 months |
| Portable if you leave the job | Yes | No |
| Full annual amount available day one | No, only what is deposited | Yes |
| Can be invested | Yes, if the custodian offers it | No |
| Can pay insurance premiums | No, apart from four narrow exceptions | No |
| Employer contributions allowed | Yes | Yes, but not required |
The 2026 HSA figures are from Revenue Procedure 2025-19 and the 2027 figures from Revenue Procedure 2026-24. The 2026 health FSA salary reduction limit of $3,400 and the $680 maximum carryover come from section 4.15 of Revenue Procedure 2025-32 and are repeated in the IRS’s own 2026 inflation adjustment announcement. One note on cross-source consistency: as of September 5, 2026, the HealthCare.gov consumer FSA page still displayed the 2025 figures of $3,300 and $660. The revenue procedure is the controlling document, and $3,400 is the 2026 number.
The 2027 health FSA and QSEHRA figures genuinely do not exist yet. The IRS publishes HSA amounts in the spring and the broad inflation package each fall, so the 2027 cafeteria plan limit is expected later in 2026. Do not trust a site quoting one today.
What Happens to Unused Money
This is the difference that decides most people’s answer.
An HSA never expires. Balances roll from year to year, stay invested, and remain yours after you stop being eligible to contribute. Losing your HSA-qualified plan stops deposits, not withdrawals. HSA rollover covers moving a balance between custodians and what happens to an old workplace account.
A health FSA is use-it-or-lose-it. Publication 969 says amounts left at the end of the plan year generally cannot be carried over, and your employer is not permitted to refund any part of the balance to you. Plans may soften this two ways, and only one of them at a time: a grace period of up to 2.5 extra months to incur expenses, or a carryover of up to $680 of 2026 funds into the following plan year. A plan that adopts a carryover cannot also offer a grace period.
Leaving your job ends an FSA. The HSA moves with you. That asymmetry compounds over a career, which is why an HSA is often described as a retirement account that happens to pay medical bills.
Can You Have Both an HSA and an FSA?
Not a regular one. Publication 969 says an employee covered by an HDHP and a general-purpose health FSA or HRA generally cannot contribute to an HSA, because the FSA counts as disqualifying other coverage. Your spouse’s general-purpose FSA can disqualify you too, since it can reimburse your expenses.
There are sanctioned pairings:
Limited-purpose FSA. Reimburses only dental, vision, and preventive care, so it does not disqualify you. This is the standard combination employers offer alongside an HSA plan, and it is worth using because dental and vision are exactly the categories a high deductible plan tends to ignore. See limited-purpose FSA for what qualifies.
Post-deductible FSA. Pays nothing until the minimum annual deductible is met, so it stays out of the way of your eligibility.
A general-purpose FSA with a zero balance at year end. Publication 969 allows HSA eligibility during a general-purpose FSA’s grace period if the balance at the end of the prior plan year was zero. Spending down to zero before December 31 is the maneuver.
Employer-funded arrangements follow a parallel set of rules. HRA vs HSA walks through which HRA designs block HSA contributions and which do not.
Which One a Cash-Pay Patient Should Want
If you pay cash prices, the HSA is the better tool, and it is not close.
It works when you have no coverage. An HSA balance is spendable for qualified medical expenses whether or not you currently have insurance. An FSA disappears the moment the job does, which is precisely when a self-payer needs it.
It has no employer dependency. Freelancers, contractors, and small business owners are locked out of FSAs entirely. HSA for the self-employed covers how to open and fund one on your own.
Bronze and catastrophic plans now qualify. For a healthy self-payer, pairing a cheap catastrophic health insurance or bronze plan with an HSA is newly workable in 2026, and a direct primary care membership under the fee caps no longer breaks it.
Both accounts pay cash rates the same way. Neither requires that a claim be filed with an insurer. A self-pay office visit, a teeth cleaning, an eye exam, or a cash-price MRI is reimbursable if it meets the qualified medical expense definition. Check what a fair cash rate looks like with the fair price tool before you spend account money, because tax-free dollars spent on an inflated price still bought an inflated price.
Take the FSA anyway if it is all you have. A $3,400 election at a 22% federal bracket plus payroll tax is real savings, and the day-one access is a genuine feature. Just estimate low, since forfeiting is the default outcome, not the exception.
Neither account replaces paying less. Before you drain a balance, run the bill through how to negotiate medical bills, and check prescription assistance programs for anything brand-name.
The Bottom Line
For 2026 the ceilings are $4,400 self-only or $8,750 family for an HSA against $3,400 for a health FSA, with the HSA rising to $4,500 and $9,000 in 2027. The HSA requires a qualifying high deductible plan but is yours permanently, rolls over, invests, and survives a job change. The FSA requires an employer, gives you the whole election on day one, and mostly evaporates at year end.
If you qualify for an HSA, fund it first and add a limited-purpose FSA for dental and vision. If you have no qualifying plan and no employer, neither account is available to you today, though HSA contribution limits is worth reading before open enrollment so you can pick a qualifying plan next cycle. Anything touching an actual filing decision belongs with a tax professional.