HSA vs. FSA Comparison: Rollover, Limits, and Eligibility

An HSA and an FSA both let you pay medical costs with pre-tax dollars, but they behave very differently once the money is in the account. The core of the HSA vs. FSA comparison: HSA funds belong to you permanently and can be invested for growth, while FSA funds generally expire at the end of each plan year and stay tied to your employer. For 2026, you can put up to $4,400 into an HSA with self-only coverage or $8,750 with family coverage, compared with a flat $3,400 for a healthcare FSA no matter how many people you cover.

Who Can Have Each Account

HSA eligibility is driven by your health insurance. You need to be enrolled in a high-deductible health plan, you can’t have other disqualifying coverage such as a general-purpose FSA, and you can’t be enrolled in Medicare.¹ You also can’t be claimed as a dependent on someone else’s return. Meet those tests and you can open one whether you’re employed, self-employed, or between jobs.

FSA eligibility runs through your employer, not your insurance. FSAs live inside cafeteria plans, which require a written employer-sponsored arrangement where every participant is an employee.² If your company doesn’t offer one, you can’t have one. But an FSA doesn’t care what kind of health plan you carry. You can pair it with a PPO, an HMO, or any other coverage your employer provides.

2026 Contribution Limits

HSA limits are adjusted for inflation each year and depend on whether your HDHP covers you alone or your family:

Self-only coverage: $4,400
Family coverage: $8,750
Catch-up contribution at age 55 or older: an extra $1,000

You and your employer can both contribute, but the combined total from all sources can’t exceed the annual limit.³ Excess contributions are hit with a 6% excise tax for every year they stay in the account until you withdraw them.

Healthcare FSAs have one cap of $3,400 for 2026, whether you’re covering just yourself or a family. That figure applies only to your salary reduction. Employers can add money on top of the cap, though most contribute little or nothing.

To fund an HSA, your health plan has to meet the IRS’s HDHP thresholds for minimum deductible and maximum out-of-pocket costs, both updated annually.⁴ FSAs have no insurance requirement at all.

What You Can Spend the Money On

Both accounts use the same federal definition of qualified medical expenses, which covers costs for diagnosing or treating disease along with dental, vision, and prescription drug expenses.⁵ Since 2020, over-the-counter medications and menstrual care products qualify without a prescription.⁶

Typical eligible costs include copayments, dental cleanings and orthodontics, eyeglasses and contacts, lab work, physical therapy, and mental health services. Cosmetic procedures generally don’t qualify unless they correct a deformity from disease, injury, or a congenital condition. Save receipts. If the IRS questions a withdrawal and you can’t document a qualifying expense, the amount is reclassified as taxable income.

The Biggest Practical Difference: Rollover vs. Forfeiture

This is where the two accounts split, and it’s the reason planners tend to favor HSAs for people who qualify.

HSA: You Keep It

Every dollar in your HSA belongs to you. The balance rolls over year after year with no cap and no expiration. If you change jobs, get laid off, or retire, the account goes with you.⁴ No employer or plan can claim the funds back. That permanence is what makes it usable as a long-term savings vehicle rather than a yearly spending account.

FSA: Use It or Lose It

Money left in an FSA at the end of the plan year is forfeited back to the employer.⁷ Federal rules give employers two ways to soften that, though neither is required and a plan can only offer one:

Carryover of up to $680 in unused funds into the next plan year (2026 limit).⁸
Grace period of an extra two and a half months after the plan year to spend the remaining balance on eligible expenses.

Read your plan document to see which one, if any, applies. Many employees assume they have a grace period their employer never adopted.

What Happens When You Leave Your Job

An HSA doesn’t change. The account is yours regardless of employment. You can keep spending from it, keep the balance invested, and even keep contributing as long as you still have qualifying HDHP coverage. Lose your HDHP and you just can’t add new money. Existing funds remain yours for medical expenses indefinitely. If you elect COBRA and your continuation coverage is HDHP-qualified, contributions can continue.

An FSA usually ends when your employment does. Any unspent balance is forfeited. The timing can hurt. If you’ve been contributing $280 a month and leave in June having barely tapped the account, you lose whatever you’ve put in. That’s why the standard advice with an FSA is to front-load spending early in the plan year. Some employers allow COBRA continuation for FSAs, but it’s rare and rarely cost-effective, since you’d pay both the employee and employer share plus an administrative fee.

Investing an HSA for Long-Term Growth

Most HSA administrators let you invest your balance in mutual funds, ETFs, stocks, and bonds once you clear a cash threshold, often $1,000 or $2,000. Gains grow tax-free, and withdrawals for medical expenses are never taxed. That makes the HSA the only account in the tax code with a tax break going in, growing, and coming out.

This is why some people with the financial room to do so pay current medical bills out of pocket and let their HSA compound for decades. A 35-year-old who maxes self-only contributions and invests can build a substantial healthcare fund by retirement, when medical costs tend to rise. After age 65, the account also works as a general retirement fund: non-medical withdrawals are taxed as ordinary income, like a traditional 401(k) or IRA distribution, without the 20% penalty that applies before that age.¹ Before 65, non-medical withdrawals trigger income tax plus that 20% penalty, which is what keeps the money earmarked for healthcare.

FSAs offer nothing comparable. There’s no investment component and no way to accumulate funds past a single plan year.

The One Structural Advantage FSAs Have

FSAs do have one edge worth knowing about. Under the uniform coverage rule, your full annual election is available on day one of the plan year, even though payroll deductions come out gradually. Elect $3,400 and hit a large dental bill in January, and you can reimburse the whole amount right away after only one paycheck’s worth has actually gone in. Your employer fronts the money and collects it back through your remaining paychecks. If you leave mid-year having spent more than you contributed, the employer can’t recover the difference from you. HSAs don’t work this way. You can only spend what’s actually in the account.

Using Both Together: The Limited-Purpose FSA

A general-purpose FSA disqualifies you from contributing to an HSA. A limited-purpose FSA does not. A limited-purpose FSA restricts reimbursements to dental and vision expenses, including cleanings, fillings, crowns, orthodontics, eye exams, glasses, and contacts.⁹ Because the coverage is narrow enough that it doesn’t overlap with the HDHP’s medical coverage, the IRS doesn’t treat it as disqualifying.

The strategy is simple. Route dental and vision costs through the limited-purpose FSA and use the HSA for everything else, or leave the HSA balance alone to grow. You can’t reimburse the same expense from both. Not every employer offers a limited-purpose FSA, so check your enrollment materials if you’re on an HDHP and want to run both.

The Medicare Timing Trap for HSA Owners

Once you enroll in Medicare Part A or Part B, your HSA contribution limit drops to zero. You can still spend existing funds tax-free, but you can’t add new money.¹ The trap is retroactive enrollment. If you’re over 65 and apply for Social Security, Medicare Part A enrollment is automatic and backdated up to six months. Contributions you made during those retroactive months become excess contributions, triggering the 6% excise tax for each year the excess remains.

The safest approach is to stop HSA contributions at least six months before you plan to enroll in Medicare. If you’re still working past 65 with employer HDHP coverage and haven’t filed for Social Security, you can keep contributing. Just be careful about timing when you do enroll. FSAs have no Medicare interaction at all.

HSA vs. FSA at a Glance

Insurance requirement: HSA requires a high-deductible health plan; FSA works with any employer-sponsored insurance.
2026 contribution cap: HSA allows $4,400 self-only or $8,750 family; FSA allows $3,400 regardless of coverage tier.³
Catch-up contributions: HSA adds $1,000 for those 55 and older; FSA has none.
Rollover: HSA balances roll over indefinitely; FSA balances are forfeited unless the employer offers a $680 carryover or 2.5-month grace period.
Portability: HSA stays with you when you leave a job; FSA is tied to your employer.
Investment options: HSA funds can be invested; FSA funds cannot.
Non-medical withdrawals: HSA allows them with income tax, plus a 20% penalty before age 65; FSA never allows them.
Day-one access: HSA limits spending to the current balance; FSA makes the full annual election available immediately.
Employer required: HSA can be opened independently; FSA must be offered through an employer’s cafeteria plan.

1
Office of the Law Revision Counsel. 26 USC 223 – Health Savings Accounts
2
Office of the Law Revision Counsel. 26 USC 125 – Cafeteria Plans
3
Internal Revenue Service. Revenue Procedure 2025-19
4
Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans
5
Office of the Law Revision Counsel. 26 USC 213 – Medical, Dental, Etc., Expenses
6
Internal Revenue Service. IRS Outlines Changes to Health Care Spending Available Under CARES Act
7
Internal Revenue Service. IRS Eligible Employees Can Use Tax-Free Dollars for Medical Expenses
8
FSAFEDS. FAQs – What Is the Use or Lose Rule
9
FSAFEDS. Eligible Limited Expense Health Care FSA Expenses