HSA & FSA Calculator

What is an HSA (Health Savings Account)?

A Health Savings Account (HSA) is a tax-advantaged personal savings account dedicated to paying for qualified medical expenses. To open and contribute to an HSA, you must be enrolled in a High-Deductible Health Plan (HDHP) and meet a few other criteria. HSAs were created by Congress in 2003 (Medicare Modernization Act) to give consumers more direct control over healthcare spending.

Key HSA features:

• Tax-deductible contributions — federal income tax + FICA (if payroll-deducted) + state income tax (most states)
• Tax-free investment growth — no taxes on dividends, interest, or capital gains
• Tax-free withdrawals for qualified medical expenses (today, retirement, anytime)
• Funds roll over indefinitely — no use-it-or-lose-it
• Fully portable — you own it; goes with you when you change jobs or retire
• Investable — most custodians allow investing balance above ~$1,000–$2,000 in stocks, ETFs, mutual funds
• 2026 contribution limits: $4,400 self-only / $8,750 family + $1,000 catch-up at age 55+

Major HSA custodians (2026): Fidelity (no fees, full investing menu), HSA Bank, Lively, HealthEquity, Optum Bank, and most major banks. Fidelity is widely considered the best for investors due to zero fees and access to all Fidelity mutual funds + ETFs.

What is an FSA (Flexible Spending Account)?

A Flexible Spending Account (FSA) is an employer-sponsored, tax-advantaged account for healthcare expenses. Unlike HSAs, FSAs don't require an HDHP — you can have an FSA with any health insurance plan your employer offers. FSAs were established in 1978 and are governed by IRC §125 ("cafeteria plans").

Three types of FSAs:

• Health FSA — for medical, dental, vision expenses. 2026 limit: $3,400 per employee.
• Dependent Care FSA (DCFSA) — for daycare, preschool, after-school care for kids under 13 (or qualifying disabled dependents). 2026 limit: $5,000 single/MFJ, $2,500 MFS.
• Limited Purpose FSA (LPFSA) — restricted to dental and vision only. Designed to pair with an HSA. 2026 limit: $3,400.

FSA "use it or lose it": Unused FSA dollars are forfeited at year-end (with two possible employer-elected exceptions: $680 carryover OR a 2.5-month grace period — never both for the same plan). This is the FSA's main drawback compared to HSAs.

FSA "front-loading": A unique FSA advantage — you can spend the full annual amount on Day 1 of the plan year, even if you've only contributed $0–$200 by then. This makes FSAs powerful for planned procedures (LASIK, orthodontics, fertility treatment) you'll fund through payroll deductions over the year.

How HSA & FSA tax savings work

Both HSAs and FSAs let you set aside pre-tax dollars for healthcare or dependent care expenses. Your contribution reduces your taxable income, so you save your marginal federal tax rate × contribution amount. If you contribute through payroll deduction (a "cafeteria plan"), you also avoid FICA tax (7.65% — Social Security + Medicare), plus state income tax in most states.

A simple example: if you're in the 22% federal bracket, contribute $3,400 to a Health FSA via payroll, and live in a 5% income tax state:

• Federal income tax saved: $3,400 × 22% = $748
• FICA tax saved: $3,400 × 7.65% = $260
• State income tax saved: $3,400 × 5% = $170
• Total tax saved: $1,178
• Effective cost of $3,400 in benefits: $2,222 (35% off)

HSA-eligible HDHP requirements

To open and contribute to an HSA, you must be enrolled in a High-Deductible Health Plan (HDHP) that meets specific IRS criteria. Not every "high deductible" plan qualifies — the IRS sets exact thresholds each year.

Other HSA eligibility rules:

• Cannot be enrolled in Medicare (Part A or B) — even if active employee
• Cannot be claimed as a dependent on someone else's tax return
• Cannot have other disqualifying health coverage (regular Health FSA, traditional HMO/PPO)
• Spouse can have an FSA but it cannot cover you (must be limited to spouse and other dependents)
• No restriction on age — you can contribute as long as you're HSA-eligible

Last-month rule: If you're HSA-eligible on December 1, you can contribute the full annual limit even if you only had HDHP coverage for part of the year. But you must remain HSA-eligible for the following 13-month "testing period," or you'll owe back tax + 10% penalty on the excess contribution.

HSA vs. FSA: which is better?

Verdict: If you have access to a high-deductible health plan, HSA wins on every dimension. FSA is only better when you don't have HDHP access or when your medical spending is high and predictable.

2026 contribution limits

The triple tax advantage of HSAs

No other account combines all three of these benefits:

Qualified medical expenses (full list)

IRS Publication 502 lists what qualifies. The list is broad — much broader than most people realize. Below is a non-exhaustive summary; check Pub 502 or your HSA/FSA administrator for specifics.

Insurance premium exceptions (HSA only): COBRA premiums, long-term care insurance premiums (with limits), Medicare premiums (Parts B, D, Advantage; not Medigap) once you turn 65, and health insurance while collecting unemployment benefits.

HSA investing basics

An HSA isn't just a savings account — it's a tax-advantaged investment account if you let it grow. Most custodians require a minimum cash balance ($1,000–$2,000) before allowing investing; above that, you can invest the rest in mutual funds, ETFs, stocks, or bonds.

Investment options vary by custodian:

• Fidelity HSA: No fees, no minimum, full menu of Fidelity ZERO funds and any stock/ETF
• Lively: Self-direct via TD Ameritrade or Schwab (free for individual; some employer plans cost $3/mo)
• HealthEquity: Curated mutual fund menu, $3.95/mo investing fee + fund expense ratios
• HSA Bank: TD Ameritrade brokerage option, ~$3/month investing fee
• Optum Bank: Curated mutual fund menu, $3/month investing fee

Long-term growth example: Maxing $8,750/year family contribution for 30 years at 7% return: $358,000 in tax-free medical + retirement savings. Compare to a taxable brokerage account with the same contributions: about $260,000 after capital gains taxes — HSA wins by ~$100K thanks to triple tax advantage.

If you have an old HSA with a bad custodian: Roll it over to Fidelity (free, no tax consequence). Direct trustee-to-trustee transfer once per 12 months. You get to consolidate fees and access better investment options.

Dependent Care FSA in detail

A Dependent Care FSA (DCFSA) covers childcare expenses for kids under 13 (or older dependents who can't care for themselves) so you (and your spouse, if married) can work or look for work. 2026 limit: $5,000 (single or MFJ) / $2,500 (MFS).

Qualifying DCFSA expenses:

• Daycare centers, preschool tuition (part of working environment)
• Before-school and after-school programs
• Summer day camps (NOT overnight camps)
• Babysitter or nanny (must report wages, file Schedule H)
• Adult day care for qualifying older dependents

DCFSA vs Child & Dependent Care Credit: You can use both, but not for the same expenses. Generally, DCFSA wins for higher earners (22%+ tax bracket) since it saves at marginal rate + FICA. For lower earners (10–12% bracket), the Child & Dependent Care Credit (35% rate at low income, phasing down) may save more. Run both calculations.

DCFSA "use it or lose it": Strict — no carryover, no grace period beyond what your employer's plan allows (typically 2.5 months). Plan carefully — don't elect $5,000 if you'll only spend $3,000.

Limited Purpose FSA (LPFSA) explained

An LPFSA is a special FSA restricted to dental and vision expenses only (plus post-deductible medical, in some cases). It exists for one purpose: to let you contribute to both an FSA AND an HSA in the same year, since a regular Health FSA disqualifies you from HSA contributions.

The HSA + LPFSA power combo:

• Max HSA: $4,400 self / $8,750 family (2026)
• Plus LPFSA: up to $3,400 (2026)
• Combined pre-tax savings: $7,800 self / $12,150 family
• At 32% combined federal + state + FICA: ~$2,500–$3,900 in annual tax savings

Use the LPFSA for predictable dental + vision spending (cleanings, glasses, orthodontics) and let your HSA grow tax-free for retirement. Best for couples with kids who have orthodontic or vision needs.

FSA carryover vs grace period rules

Health FSA "use it or lose it" has two possible employer-elected exceptions (NOT both — your plan picks one, or neither):

Check your specific plan — your HR or benefits portal should clearly state which options apply.

HSA as a backup retirement account

After age 65, an HSA functions essentially like a Traditional IRA — you can withdraw for any purpose without the 20% penalty (you'd just owe ordinary income tax on non-medical withdrawals). Combined with the tax-free withdrawals for medical expenses, the HSA is uniquely flexible.

Optimal retirement saving order:

1. 401(k) up to employer match (free money)
2. Max HSA ($4,400 / $8,750 + $1,000 catch-up at 55+) — triple tax advantage
3. Roth IRA ($7,000 / $8,000 with catch-up at 50+)
4. Continue 401(k) up to annual limit ($24,500 + $7,500 catch-up at 50+ in 2026)
5. Taxable brokerage for additional savings

"Save receipts, withdraw later" strategy: Pay current medical expenses out of pocket (not from HSA). Save the receipts. Let the HSA invested balance grow for decades. In retirement, reimburse yourself for those decades-old receipts — totally tax-free withdrawals from a now-massive balance. There's no time limit on receipts.

Estimated retirement medical costs (Fidelity 2025): A 65-year-old retiring couple needs ~$330,000 to cover health expenses through retirement. Maxing your HSA from age 30–65 builds well over $1M to cover this — tax-free.

State tax treatment (CA & NJ caveats)

Most states with income tax conform to federal HSA treatment — your HSA contributions reduce state taxable income just like federal. Two notable exceptions:

• California: Does NOT allow HSA deduction for state income tax. CA also taxes HSA investment growth annually. Effective state tax rate at 9.3% top bracket: ~$815/year of "state HSA tax" on a $8,750 family contribution.
• New Jersey: Same — no state HSA deduction. NJ top rate is 10.75%, so state HSA cost is similarly high.

If you live in CA or NJ, your HSA still wins on federal + FICA savings, but reduce expected total tax savings by your state marginal rate. Some workers in these states still find HSAs worthwhile for the federal benefits and long-term growth; others prefer FSAs to avoid the state tax mismatch.

All other 48 states + DC: Full conformity. HSA contributions reduce state taxable income, growth is tax-deferred, and qualified withdrawals are tax-free at the state level. The 9 no-state-tax states (TX, FL, NV, NH, SD, TN, WA, WY, AK) effectively give you only federal savings — but no state tax to worry about either way.

Open enrollment timing

FSA and HSA elections are typically made during your employer's open enrollment period — usually October through November for January 1 plan year start. You select your annual contribution amount; payroll deductions start January 1.

Mid-year changes (Qualifying Life Events): You can change your FSA/HSA election mid-year only after a "qualifying life event" — marriage, divorce, birth, adoption, death, change in spouse's employment, change in custody, dependent eligibility change, etc. Submit changes within 30 days of the event through your HR portal.

HSA flexibility advantage: Unlike FSAs (which are locked in unless QLE), you can adjust HSA contributions mid-year for any reason. Just submit a new payroll deduction form to HR. This makes HSAs much more forgiving for life changes.

10 optimization strategies

1. HSA + LPFSA combo: If your employer offers both, max your HSA AND contribute up to $3,400 in LPFSA for dental/vision. Combined pre-tax savings: $7,800–$12,150.
2. Front-load FSA in January: Spend the full annual amount on Day 1. Useful for planned procedures (LASIK, orthodontics, fertility, planned surgeries).
3. Use HSA as backup retirement: Max it, invest aggressively, save receipts for tax-free withdrawals later.
4. Stop HSA before Medicare: Halt HSA contributions starting the month you enroll in Medicare (typically age 65). Medicare disqualifies you. Pro-rate the year carefully if you enroll mid-year.
5. DCFSA vs Child & Dependent Care Credit: Run both calculations. DCFSA usually wins for high earners; credit may win for lower-income families with limited childcare costs.
6. Move HSA to Fidelity: If your custodian charges fees or has limited investment options, transfer to Fidelity HSA — zero fees, full investment menu.
7. Pair employer HSA + spouse FSA carefully: A general-purpose Health FSA on either spouse disqualifies the HSA-eligible spouse from HSA contributions. Use LPFSA on FSA spouse to preserve HSA eligibility for the HSA spouse.
8. Use the last-month rule strategically: If HSA-eligible by Dec 1, you can contribute the full year's limit even with partial-year coverage. Watch the 13-month testing period to avoid penalties.
9. After 65, treat HSA like Traditional IRA: Withdraw for any purpose at ordinary tax rates (no 20% penalty). Continue using for tax-free medical including Medicare premiums.
10. Reimburse old expenses anytime: No deadline. Save receipts forever. Pull money out tax-free decades later for medical costs incurred any time after the HSA was opened.

8 common HSA/FSA mistakes

1. Over-electing FSA contributions. Use-it-or-lose-it means you forfeit unused dollars. Be conservative — election should match realistic out-of-pocket spending.
2. Treating HSA like a checking account. Spending every contribution defeats the purpose. Let it grow tax-free for medical retirement costs.
3. Enrolling in Medicare without stopping HSA. Excess contributions trigger 6% annual excise tax. Stop contributions the month before Medicare enrollment effective date.
4. Spouse FSA disqualifying your HSA. If your spouse has a regular Health FSA, you cannot contribute to an HSA. Switch their plan to LPFSA, or skip your HSA that year.
5. Missing receipts for HSA withdrawals. The IRS can audit and demand proof that withdrawals were for qualified medical expenses. Save digital copies forever.
6. Not investing HSA balance. Cash-only HSA earns minimal interest; invested HSA grows ~7% annually. Over 30 years, that's 5–10× more wealth.
7. Forgetting Last-Month Rule testing period. If you contribute the full year on the last-month rule, you must remain HSA-eligible for the next 13 months or pay back tax + penalty.
8. Using Health FSA for ineligible expenses. Vitamins without prescription, gym memberships, cosmetic procedures — all denied. Check Pub 502 first.

Glossary of key terms

Frequently asked questions