HSA Growth Calculator
A Health Savings Account is the only account in the US tax code with three separate tax advantages at once, which makes it the most efficient retirement vehicle most people have access to — and the one most often used as a chequing account instead.
Triple Tax Advantage
| Stage | HSA | 401(k) | Roth IRA |
|---|---|---|---|
| Contributions | Deductible | Deductible | Taxed |
| Growth | Untaxed | Untaxed | Untaxed |
| Qualified withdrawals | Untaxed | Taxed | Untaxed |
It Becomes an IRA at 65
Before 65, non-medical withdrawals are taxed and carry a penalty. After 65 the penalty disappears and the account behaves like a traditional IRA — taxed as income for non-medical use, still entirely tax-free for medical. Since healthcare is one of the largest expenses in retirement, that ceiling is rarely reached.
The Strategy Most People Miss
You can pay medical costs out of pocket, keep the receipts, and reimburse yourself from the HSA years later. There is no deadline on reimbursement.
That turns the HSA into a tax-free growth account with an escape hatch: the money compounds untouched for decades, and a folder of old receipts lets you withdraw tax-free at any point. Spending the HSA on current bills instead forfeits exactly the compounding that makes it worth having.
Eligibility Is Conditional
You must be enrolled in a qualifying high-deductible health plan, and you must not be enrolled in other disqualifying coverage — including Medicare. Enrolling in Medicare ends contributions, and there is a six-month lookback that catches people who sign up at 65 while still contributing.
Contribution limits differ for individual and family coverage, with a catch-up amount from 55, and are indexed annually.
Where It Sits in the Order
The usual priority is: 401(k) up to the employer match, then the HSA to its limit, then back to the 401(k) or an IRA. The HSA outranks further 401(k) contributions precisely because of the third tax advantage.
Investing the Balance
Most custodians hold contributions in cash by default and require a minimum before allowing investment. Cash earns nothing and the account's whole advantage is tax-free *growth* — check whether yours is invested, because a great many are not.
The Projection Behind This Page
Starting from $10,000, adding $200 a month at 7%:
| Year | Deposited | Balance | Growth | Growth on deposits |
|---|---|---|---|---|
| 1 | $12,400 | $13,201 | $801 | 6% |
| 5 | $22,000 | $28,495 | $6,495 | 30% |
| 10 | $34,000 | $54,714 | $20,714 | 61% |
| 20 | $58,000 | $144,573 | $86,573 | 149% |
The Formula
``
A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) ÷ (r/n)]
└── initial principal ──┘ └────── regular contributions ──────┘
``
The second term usually dominates. On these numbers the $200 monthly contribution accounts for the larger share of the final balance, which is the practical lesson: how much you add matters more than the rate, right up until the balance gets large.