This article is general information, not tax, insurance, legal or financial advice. Account rules vary by country, employer and year. The comparisons below are common patterns, and the details that apply to you are in your plan documents or from a qualified professional.
Why the two get confused
A health savings account (HSA) and a flexible spending account (FSA) are both ways to set money aside for care costs, often with favorable tax treatment. They have similar abbreviations, similar purposes and similar-looking enrollment screens. Underneath, they work quite differently. The main differences come down to who owns the account, what happens to leftover money, and who is allowed to have one.
Ownership
HSA. The account is generally owned by you, much like a bank account. It is typically held with a financial institution, and the balance belongs to you even if you change jobs or health plans.
FSA. The account is part of an employer’s benefit plan. The employer sponsors it, and it is typically tied to your employment. If you leave, access to the account usually ends, with some limited exceptions for claims.
Ownership is the root of most other differences. Something you own can travel with you and be saved over many years. Something that belongs to a workplace plan has to follow the plan’s rules.
Rollover and year-end balances
HSA. Unused money generally stays in the account and carries forward from one year to the next with no deadline. Many people treat it as long-term savings for care costs, and some accounts allow the balance to be invested, which comes with risk.
FSA. The classic rule is use-it-or-lose-it. Money not spent by the end of the plan year may be forfeited. Employers may allow either a short grace period or a limited carryover, and some allow neither. Your plan chooses, so check before you decide how much to elect.
For anyone whose care costs are uncertain, this single difference can be decisive. If you are unsure you will use the money, a balance that rolls over is less stressful than one that might expire.
Who can have one
HSA. Eligibility is usually tied to your health insurance. Typically you must be enrolled in a qualifying high-deductible plan, and there are often other conditions, such as not having certain other kinds of coverage. The definition of a qualifying plan is set by rules that can change, so the plan itself usually states whether it qualifies.
FSA. Eligibility is tied to your employer. If your employer offers an FSA and you are an eligible employee, you can usually sign up during open enrollment regardless of which health plan you have. There is generally no requirement to have a particular kind of plan, though your employer’s rules apply.
This is why people on a traditional low-deductible plan often cannot open an HSA but may still use an FSA, while people on high-deductible plans might be able to choose an HSA.
Contributions and limits
Both accounts generally have a government-set yearly limit, and both limits typically change over time. Employers may add their own limits to an FSA. For an HSA, the limit may count contributions from you, your employer and anyone else together, and it can differ by individual or family coverage.
For an FSA, you choose an amount before the plan year and it is deducted from pay in installments. For an HSA, contributions can often be adjusted during the year, and the money that can be spent is generally what has actually been deposited. By contrast, many FSAs make the full yearly election available early in the year.
Access to money
HSA. You can generally spend only what is in the account at the time. If the balance is low early in the year, you may have to pay out of pocket and reimburse yourself later, since many HSAs let you do that for expenses that occurred after the account was opened.
FSA. Many health FSAs make the whole election available from the start of the plan year. That can be helpful for an early expensive appointment, though it ties to the employer relationship.
What the money can be used for
Both accounts are generally meant for qualifying health costs, and the definitions overlap a great deal. Dental, vision, prescriptions and copays are widely accepted. What counts as eligible medical expenses depends on the account and the plan. Some employers also offer narrower versions of FSAs, such as accounts limited to dental and vision, which work differently from a standard one.
Can you have both?
Often, the answer is “not in the standard form.” Because an HSA is typically tied to a high-deductible plan, having a general-purpose health FSA at the same time can make you ineligible to contribute to the HSA. Restricted versions of an FSA, limited to certain expenses, are sometimes designed to work alongside an HSA. The rules here are technical, and a mistake can have tax consequences, so confirm with your benefits team or a tax professional before enrolling in both.
Job changes and retirement
An HSA moves with you when you change jobs, and some people continue using it after they retire. An FSA generally does not follow you. Because retirement savings and long-term care costs are on many people’s minds, the portability of an HSA is a major part of why it is discussed so often. That said, the right choice depends on your health, your finances and the plans available to you.
Quick comparison
| Feature | HSA | FSA |
|---|---|---|
| Who owns it | You | Employer’s plan |
| Year-end balance | Generally carries over | May be forfeited, with possible grace period or carryover |
| Eligibility | Usually requires a qualifying high-deductible plan | Usually requires employer offering it |
| Follows you to a new job | Generally yes | Generally no |
| Can be invested | Often an option | Generally not |
Thinking about which fits
Neither account is better in every situation. Factors that tend to matter include:
- Whether you are in or considering a high-deductible plan
- How predictable your care costs are
- Whether you want to save money for future years or only for this year
- Whether your employer offers the account and adds funds to it
- How comfortable you are with the rules and paperwork
Your own numbers and your own plan will decide the outcome, and no one can promise a particular result. If you are close to a decision, a benefits representative or tax professional can help you check the current rules.