What Is an HSA, and Why It Beats a 401(k) and a Roth IRA on Taxes

What is an HSA? A Health Savings Account is a tax-advantaged account paired with a qualifying high-deductible health plan. It is the only account in the U.S. tax code that is untaxed at all three points: contributions are deductible, growth is untaxed, and withdrawals for qualified medical expenses are untaxed. Contributions made through payroll also escape Social Security and Medicare tax, which no retirement account does. Every tax-advantaged account in the U.S. gives you two of the three possible breaks. A traditional 401(k): deductible going in, taxed coming out. A Roth: taxed going in, tax-free coming out.

The HSA gives you all three. Deductible going in, untaxed while it grows, untaxed coming out for medical expenses. There is no other account like it, and most people who have one treat it as a debit card for co-pays.

What is an HSA and who can open one?#

Item	2026 amount
HSA limit, self-only coverage	$4,400
HSA limit, family coverage	$8,750
HSA catch-up, age 55+Per person. Spouses each need their own HSA to both use it.	$1,000
Minimum HDHP deductible (self / family)Below this, the plan is not HSA-qualified no matter what HR calls it.	$1,700 / $3,400
Maximum HDHP out-of-pocket (self / family)	$8,500 / $17,000

To contribute you must be covered by a qualifying high-deductible health plan and have no other disqualifying coverage: a general-purpose FSA, most secondary health plans, and any part of Medicare will end eligibility.

The limits are per household situation, not per account. Two spouses with family coverage share the family limit, though each can add their own $1,000 catch-up at 55 only if each has their own HSA.

How do you turn an HSA into a retirement account?#

Most people use an HSA as a pass-through: money in, medical bill out, balance near zero. That captures the tax deduction and nothing else.

The version that matters has three parts.

1. Pay current medical costs from cash, if you can. Leave the HSA untouched.

2. Invest the balance. Nearly every HSA custodian offers investment options above a small cash threshold, and nearly every accountholder leaves the money in a cash account earning almost nothing. Tax-free growth is worthless if there is no growth.

3. Keep every receipt. This is the mechanism that makes it work.

The receipt rule#

There is no deadline for reimbursing yourself from an HSA. A qualified medical expense incurred today can be reimbursed tax-free in thirty years, as long as:

• The expense was incurred after you established the HSA.
• You did not already deduct it elsewhere or reimburse it from another account.
• You kept the documentation.

So you pay a $2,400 dental bill from cash in 2026, save the receipt, and let the HSA keep compounding. In 2056, that $2,400 has become a much larger sum, and you can withdraw $2,400 of it completely tax-free at any time by producing the receipt.

You have effectively converted decades of investment growth into tax-free money using a receipt as the key.

What happens to an HSA at 65?#

At 65, the penalty for non-medical withdrawals disappears. Withdrawals for non-medical purposes are taxed as ordinary income: exactly like a traditional IRA.

Which sets the floor. Worst case, an HSA is as good as a traditional IRA. Best case, everything comes out tax-free against medical expenses.

And medical expenses in retirement are large and certain. Medicare premiums (except Medigap), long-term care insurance premiums up to age-based limits, dental, vision, hearing aids: all qualified. The one category to know about: Medicare Part B and Part D premiums are qualified expenses, Medigap premiums are not.

What is the difference between an HSA and an FSA?#

Frequently confused, and materially different.

The one genuine FSA advantage is that the full annual election is available from the first day of the plan year even though you fund it monthly. For someone with a known large expense in January, that matters.

Choosing the plan to get one#

An HSA-qualified plan means a higher deductible, and that is a real trade. It works well if:

• You are generally healthy and use little care.
• You could absorb the full deductible from savings if you had to.
• You will actually fund the HSA, rather than pocketing the premium saving.

It works badly if a single unexpected bill would go on a credit card. In that case the richer plan is the right answer regardless of the tax treatment, and the HSA is not worth restructuring your health coverage to reach.

That is what is an HSA worth answering properly for: not a health account you spend down each year, but the most tax-efficient retirement account available to anyone who qualifies. Do the comparison properly: annual premium plus expected costs plus worst case, for both plans, with the tax saving on the HSA contribution credited to the HDHP side. The HDHP frequently wins even in a moderate year once the tax benefit is counted.

What counts as a qualified medical expense?#

Broader than most accountholders assume, which is why the receipt strategy works so well.

Clearly qualified: deductibles, copays and coinsurance, prescriptions, dental work including orthodontics, vision including glasses, contacts and laser surgery, mental health care, physical therapy, chiropractic, hearing aids, and most medical equipment. Over-the-counter medicines and menstrual products qualify without a prescription. So does long-term care insurance, up to age-based limits.

Qualified with a condition: health insurance premiums generally do not qualify, with four exceptions worth knowing. COBRA premiums, premiums while receiving unemployment compensation, Medicare Part A, B and D premiums after 65, and long-term care premiums all do. Medigap premiums do not, which surprises people planning for retirement.

Not qualified: cosmetic procedures, gym memberships without a diagnosis, most supplements, and anything you have already reimbursed from an FSA or deducted on your return.

The published reference is IRS Publication 969, and the annual limits come from Revenue Procedure 2025-19. Both are worth a bookmark, because the list moves.

Two practical notes. Expenses only qualify if incurred after you opened the account, which is a good reason to open one the day you become eligible even with a token balance. And a spouse or dependant's expenses qualify from your HSA even if they are not on your health plan, which quietly doubles the useful scope for most families. Where the HSA sits against your other accounts is covered in which retirement account to fill first, and the health plan side is in how health insurance works.

What mistakes should you avoid?#

Leaving it in cash. The most common and most expensive.

Not opening one at all because the employer did not push it.

Contributing while on Medicare. Eligibility ends when Medicare begins, and Part A enrollment can be applied retroactively up to six months when you claim Social Security after 65. Excess contributions carry penalties. Plan the stop date carefully.

Missing the last-month rule. If you are HSA-eligible on 1 December, you can generally contribute the full annual amount for that year, but you must remain eligible for the whole of the following year or face taxes and penalties.

Using it as an emergency fund. Before 65, non-medical withdrawals cost income tax plus 20%. That is a worse outcome than almost any alternative.