Using your HSA in retirement: the rules that unlock tax-free money

You spent your working years building an HSA — maybe investing it, maybe banking receipts. Retirement is when it pays off, and the rules quietly get more generous at 65. The account that was strictly for medical costs becomes a flexible, tax-advantaged retirement asset: it pays most Medicare premiums tax-free, it converts to a penalty-free quasi-IRA for any purpose, and every receipt you banked over the years becomes tax-free cash on demand. Knowing how to draw it down is worth real money.

The rules that change at 65

• The 20% penalty for non-medical withdrawals disappears. After 65, HSA money used for anything counts as ordinary income (like a traditional IRA) — no penalty. Used for qualified medical expenses, it's still fully tax-free.
• You can pay Medicare premiums tax-free: Part B, Part D, and Medicare Advantage premiums are all HSA-eligible after 65. (Medigap/supplement premiums are the notable exception — not eligible.)
• Contributions must stop once you enroll in any part of Medicare — but spending never has to stop.
• A spouse inherits your HSA as their own HSA, tax-free; anyone else inherits it as fully taxable income in one year.

Paying Medicare premiums from the HSA

This is one of the cleanest uses. Medicare Part B alone runs roughly $185/month per person (more for higher earners), and Part D and Advantage premiums add to it. All of these can be paid from HSA funds tax-free after 65 — effectively giving you a 22–32% discount on a large, recurring retirement expense. If your premiums come out of your Social Security check automatically, you can still reimburse yourself from the HSA for those premium amounts.

A sensible drawdown order

1. Pay current medical costs and Medicare premiums (not Medigap) from the HSA first — that's tax-free money doing its best job.
2. Reimburse banked receipts whenever you want tax-free cash for any purpose — a uniquely flexible source with no age or penalty strings.
3. For heirs: if your beneficiary isn't your spouse, spend the HSA down late in life, because a non-spouse inherits it as fully taxable income in a single year.
4. Coordinate with IRMAA: HSA withdrawals for qualified expenses don't count as income, so they don't raise MAGI or trigger Medicare surcharges — a quiet planning advantage.

The bottom line

In retirement the HSA sheds its restrictions: after 65 the penalty vanishes, it pays Medicare Part B, D, and Advantage premiums tax-free, banked receipts become tax-free cash for any purpose, and qualified withdrawals never raise your income for IRMAA. Draw it down by paying current medical costs and eligible premiums first, cash in old receipts when you want flexible tax-free money, and remember the two carve-outs — no Medigap premiums, and non-spouse heirs pay tax. Handled well, it's the most tax-efficient dollar in your retirement.