The HSA Guide: How to Use a Health Savings Account to Build Wealth

The HSA is the only account that gives you a triple tax advantage — and most people use it wrong. Here's how to turn a health savings account into one of the most powerful wealth-building tools you have.

What Is an HSA (And How Is It Different From an FSA)?

A Health Savings Account (HSA) is a tax-advantaged account designed to pay for qualified medical expenses. But it's also, if you use it strategically, one of the best retirement accounts available to anyone.

Before diving in, it's worth distinguishing it from the FSA:

HSA (Health Savings Account)

Attached to a High-Deductible Health Plan (HDHP)
Funds roll over year to year — forever
You own the account; it moves with you if you change jobs
Can be invested in stocks, bonds, and funds
No "use it or lose it" rule

FSA (Flexible Spending Account)

Available with most employer health plans (including non-HDHPs)
"Use it or lose it" — most balances expire at year end
Cannot be invested
Employer-owned

The FSA has its place for predictable, near-term medical costs. But the HSA, when used correctly, is in a different league entirely.

The Triple Tax Advantage — Explained

No other account in the U.S. tax code does what an HSA does:

Contributions are tax-deductible — Money you put in reduces your taxable income, just like a Traditional IRA or 401(k).
Growth is tax-free — Dividends, interest, and capital gains inside your HSA are never taxed.
Withdrawals are tax-free — As long as you use the money for qualified medical expenses (at any point in your life), withdrawals are completely tax-free.

Compare this to a 401(k): contributions are pre-tax, growth is tax-deferred, but withdrawals are taxed as ordinary income.

Or a Roth IRA: contributions are post-tax, growth is tax-free, withdrawals are tax-free — but only two of the three tax advantages apply.

The HSA hits all three. For qualified medical expenses, it's the most tax-efficient account that exists.

2024 and 2025 Contribution Limits

Year	Individual Coverage	Family Coverage	Catch-Up (55+)
2024	$4,150	$8,300	+$1,000
2025	$4,300	$8,550	+$1,000

To contribute to an HSA, you must be enrolled in a High-Deductible Health Plan (HDHP) — in 2025, that means a plan with a minimum deductible of $1,650 (individual) or $3,300 (family). You also cannot be enrolled in Medicare or claimed as a dependent on someone else's taxes.

The Fatal Mistake: Leaving HSA Money in Cash

Most people treat their HSA like a checking account — money in, medical bills paid, repeat. That's leaving an enormous amount of money on the table.

The smarter approach: Invest your HSA funds. Most HSA providers (Fidelity HSA, HealthEquity, Lively) allow you to invest your balance in index funds once it exceeds a minimum threshold ($0–$2,000 depending on the provider).

A $4,000/year HSA contribution invested in a low-cost index fund for 25 years at 7% average annual return grows to approximately $270,000 — tax-free if used for medical expenses.

That same $4,000/year left in cash earning 0.5% would be worth about $115,000. You leave $155,000 on the table by not investing.

The best HSA for investors is Fidelity's HSA — no account fees, no minimum to invest, and access to zero-fee index funds.

The "Pay Out of Pocket Now, Reimburse Later" Strategy

Here's the advanced move that maximizes HSA wealth-building:

When you have qualified medical expenses now, don't withdraw from your HSA. Pay out of pocket from your regular checking account. Save the receipt. Let your HSA investments compound untouched.

Years (or decades) later, you can reimburse yourself for those old expenses — with no time limit for reimbursement. The IRS doesn't require you to withdraw HSA funds in the same year as the expense; you just need to have incurred the expense after you opened the HSA.

The strategy: accumulate years of medical receipts. Let the HSA grow tax-free for 20–30 years. Then reimburse yourself for all those old expenses — essentially making tax-free withdrawals for non-medical purposes, penalty-free.

Using an HSA in Retirement

At age 65, the HSA changes character:

Withdrawals for qualified medical expenses remain 100% tax-free
Withdrawals for any reason (including non-medical) are taxed as ordinary income — but with no penalty, just like a Traditional IRA

This means after 65, your HSA functions as both a medical account and a bonus Traditional IRA. Given that the average couple retiring today will need $315,000 in healthcare costs in retirement (Fidelity's estimate), having a fully funded, invested HSA is one of the most strategic things you can do.

HSA funds can pay for Medicare premiums, long-term care insurance premiums, and most out-of-pocket medical costs tax-free. This is money you'd have to spend anyway — the HSA just lets you spend pre-tax (or tax-free growth) dollars instead of after-tax dollars.

Why It's the Most Underused Retirement Account

In 2023, only 4% of HSA account holders invested their balance. Most people either don't know they can invest, or they keep the money liquid for anticipated medical expenses.

If you're healthy and can afford to pay current medical bills out of pocket, the HSA is the single most underutilized wealth-building account available to you. Max it out first — before your IRA, after your 401(k) employer match.