HSA vs IRA for FIRE: Which Wins on Tax Efficiency?

The HSA (Health Savings Account) is the most tax-advantaged account available in the US, yet wildly underutilized. Contributions are pre-tax (reducing taxable income now), growth is tax-free, and qualified medical withdrawals are tax-free — a genuine triple tax advantage that neither Roth IRA nor traditional 401k can match. For FIRE practitioners on high-deductible health plans, maximizing HSA contributions is arguably the #1 priority before even maxing a 401k.

HSA for FIRE works best as a "stealth IRA." Invest your HSA in index funds, pay all current medical bills out-of-pocket (if you can afford to), and let the HSA grow untouched for decades. Save all medical receipts — there's no time limit on reimbursements, so you can reimburse yourself 20 years later for medical expenses paid today. At 65, HSA withdrawals for any purpose (not just medical) are taxed at ordinary income rates — essentially becoming a traditional IRA. The difference: medical withdrawals at any age remain completely tax-free.

Priority order for FIRE savings accounts: (1) 401k to employer match (immediate 100% return); (2) HSA max ($4,150 individual / $8,300 family for 2025); (3) Roth IRA ($7,000); (4) 401k max ($23,500); (5) Mega backdoor Roth if available; (6) Taxable brokerage. The HSA rises to #2 because of its unmatched triple tax advantage and role as a healthcare reserve.

Roth IRA advantages over HSA: no healthcare requirement (anyone with earned income can contribute), higher investment flexibility (any broker), and no required connection to a high-deductible health plan. Roth IRA is always available; HSA requires an HDHP. For those with HDHP access, HSA and Roth IRA are complementary — use both. For those without HDHP access, Roth IRA is the next best tax-free vehicle.