Two Tax-Advantaged Accounts, One Goal: Lower Healthcare Costs
If you have seen “FSA/HSA” on a benefits enrollment form and wondered what it means, you are looking at two of the most effective tools for reducing out-of-pocket medical spending. What is FSA/HSA? An FSA (Flexible Spending Account) and an HSA (Health Savings Account) both let you set aside pre-tax money for qualified medical expenses — but they work under different rules, serve different health plan structures, and offer different long-term advantages.
Roughly 56 million Americans had access to an HSA-eligible plan in 2024, according to Devenir Research, while an estimated 30 million workers had access to a healthcare FSA. Understanding both accounts — and knowing when you can use them together — can save you thousands of dollars over the course of your career.
What Is an FSA?
A Flexible Spending Account is an employer-sponsored benefit that allows you to contribute pre-tax income to pay for qualified medical expenses. For 2025, the IRS caps contributions at $3,300 per employee. Your employer deducts the amount in equal installments from your paychecks before taxes are calculated.
The key features of an FSA: your full annual election is available on day one of the plan year (the uniform coverage rule), contributions reduce your federal income tax, state income tax (in most states), and FICA taxes, and the account is owned by your employer — you lose access if you leave the job.
The major limitation is the use-it-or-lose-it rule. Unspent FSA funds are generally forfeited at year-end, though some employers offer a grace period (up to 2.5 months) or a rollover (up to $660 for 2025). For a deeper dive, see our guide on how FSAs work.
What Is an HSA?
A Health Savings Account is a tax-advantaged account available to individuals enrolled in a high-deductible health plan (HDHP). For 2025, the IRS defines an HDHP as a plan with a minimum deductible of $1,650 for self-only coverage or $3,300 for family coverage.
HSA contribution limits for 2025 are $4,300 for individual coverage and $8,550 for family coverage, plus a $1,000 catch-up contribution for those aged 55 and older. The HSA offers a triple tax advantage: contributions are tax-deductible (or pre-tax through payroll), investment growth is tax-free, and withdrawals for qualified medical expenses are tax-free.
Unlike an FSA, HSA funds roll over indefinitely. You own the account personally — it stays with you when you change jobs or retire. Many HSA holders invest their balances in mutual funds or index funds, treating the account as a supplemental retirement vehicle. Our HSA benefits guide explains why financial advisors call it the most tax-efficient account in America.
FSA vs. HSA: Side-by-Side Comparison
The differences between the two accounts drive different strategies for different people.
Eligibility. An FSA is available with any employer-sponsored health plan. An HSA requires enrollment in an HDHP. 2025 contribution limits. FSA: $3,300. HSA: $4,300 individual, $8,550 family. Fund availability. FSA: full election on day one. HSA: only what has been deposited. Rollover. FSA: generally use-it-or-lose-it (with possible grace period or $660 rollover). HSA: unlimited rollover, forever. Portability. FSA: employer-owned, lost if you leave. HSA: individually owned, fully portable. Investment. FSA: no investment option. HSA: can invest in stocks, bonds, mutual funds. Tax benefit. Both: pre-tax contributions and tax-free qualified spending. HSA adds: tax-free investment growth.
For a more detailed analysis, visit our HSA and FSA comparison.
Can You Have Both an FSA and an HSA?
This is one of the most common questions when people ask “what is FSA/HSA” — and the answer is nuanced.
You cannot have a general-purpose healthcare FSA and an HSA at the same time. A general FSA disqualifies you from making HSA contributions because the FSA provides first-dollar coverage for medical expenses, which conflicts with the HDHP requirement.
However, you can pair an HSA with a Limited Purpose FSA (LPFSA). The LPFSA covers only dental and vision expenses, so it does not interfere with HSA eligibility. This combination gives you two pre-tax accounts: one for dental and vision (LPFSA), and one for everything else (HSA). Some employers also offer a post-deductible FSA that becomes a general-purpose FSA after you meet your HDHP deductible.
You can always have a Dependent Care FSA alongside an HSA — dependent care accounts cover childcare expenses, not medical expenses, so there is no conflict. Learn more in our LPFSA guide and our article on dependent care FSA eligible expenses.
Which Account Is Right for You?
Your health plan determines your primary option. If you are enrolled in a traditional PPO or HMO, the FSA is your tax-advantaged tool. If you have an HDHP, the HSA is typically the stronger choice due to its rollover, investment, and portability features.
Choose the FSA If:
Your employer offers a traditional (non-HDHP) health plan. You have predictable medical expenses you want to cover with pre-tax dollars. You value having the full balance available on day one of the plan year. You do not mind the use-it-or-lose-it limitation.
Choose the HSA If:
You are enrolled in a qualifying high-deductible health plan. You want to build a long-term, tax-free medical savings balance. You prefer account portability. You are comfortable with the HDHP’s higher upfront cost-sharing. You want investment options for your healthcare savings.
Use Both (HSA + LPFSA) If:
You have an HDHP with HSA eligibility and your employer offers a Limited Purpose FSA. You have significant dental or vision expenses. You want to maximize your total pre-tax healthcare allocation.
What Both Accounts Cover
Both FSAs and HSAs cover the same universe of qualified medical expenses as defined by IRS Publication 502 and expanded by the CARES Act of 2020. That includes doctor visits, prescriptions, OTC medications, dental care, vision care, mental health services, medical equipment, menstrual products, and sunscreen. The LPFSA narrows that list to dental and vision only.
For the full product-by-product breakdown, see our FSA eligible items list and our HSA approved items list.
Maximizing Both Accounts Together
If you have access to both an HSA and an LPFSA, here is how to coordinate them. Fund your LPFSA at a level that covers your expected dental and vision costs — cleanings, exams, glasses, contact lenses, and any planned dental work. Maximize your HSA contributions to build long-term savings. Pay non-dental, non-vision medical expenses from your HSA (or out of pocket if you want your HSA to grow). Reimburse yourself from your HSA later using the pay-and-reimburse strategy.
This approach gives you the maximum pre-tax savings while preserving the growth potential of your HSA. For reimbursement mechanics, see our HSA reimbursement guide.
Frequently Asked Questions
Can I switch from an FSA to an HSA?
Yes, but timing matters. If you switch from a traditional health plan to an HDHP, you can open an HSA. However, any remaining general-purpose FSA balance from the prior plan year can delay your HSA eligibility. Consult your benefits administrator for your specific transition timeline.
What if both my spouse and I have FSAs?
Each spouse can contribute up to the IRS maximum to their own FSA. You cannot submit the same expense to both accounts, but you can split family medical expenses between them to maximize your combined pre-tax benefit.
Do FSA and HSA cover the same things?
Yes. Both accounts use the same IRS definition of qualified medical expenses (Section 213(d) and Publication 502). The eligible products and services are identical for a general-purpose FSA and an HSA. The LPFSA restricts coverage to dental and vision only.
Is it better to have a higher FSA or a higher HSA contribution?
If you have access to both (via LPFSA + HSA), prioritize maximizing your HSA first. HSA contributions offer the triple tax advantage and unlimited rollover. Fund your LPFSA with whatever dental and vision spending you can predict with confidence.
Use Your FSA/HSA to Its Full Potential
Understanding what FSA/HSA means and how the two accounts operate — separately or together — puts you in a stronger position to manage healthcare costs. Whether you have one account or both, the pre-tax savings are significant and the rules are manageable once you learn them. Review your benefits options at your next open enrollment, estimate your medical expenses, and allocate your contributions strategically. For more guidance, explore our healthcare costs guide and our healthcare policy guide.