HSA Calculator

How the HSA Calculator works

A Health Savings Account is the most tax-efficient account most Americans have access to, and also the one most often left half-used. This tool applies the 2026 contribution limits to your coverage type and age, caps your combined employer + employee contributions at that limit, and estimates the federal income tax you save on the portion you contribute yourself.

The point of the calculation isn't just the tax number. It's the remaining room figure: how much more you could still put in this year before the IRS ceiling stops you. That number is what tells you whether to adjust your payroll deduction before December 31.

The formula

The 2026 base limits are $4,400 for self-only coverage and $8,750 for family coverage. The $1,000 catch-up is fixed by statute and isn't adjusted for inflation, which is why it has sat at $1,000 for years while the base limits climb. Note that the tax saving applies to your contribution only — money your employer puts in was never in your taxable income to begin with, so there's nothing further to save on it.

Worked example

A 57-year-old with family coverage has a limit of $8,750 + $1,000 = $9,750. Their employer contributes $1,500, so their own maximum is $8,250. If they contribute $6,000 through payroll, the account receives $7,500 for the year and $2,250 of room goes unused. At a 24% marginal rate, their $6,000 contribution saves roughly $1,440 in federal income tax — and contributing the remaining $2,250 would save about $540 more.

If the same contributions were made through an employer's payroll (a cafeteria plan), they also avoid FICA taxes — an additional 7.65% that this calculator doesn't include, since it depends on how you fund the account. Payroll contributions are meaningfully better than writing a check to your HSA custodian and deducting it at filing time.

Common mistakes

• Treating the employer contribution as a bonus on top of your limit rather than a slice out of it.
• Assuming family coverage means two people each get their own limit — one family limit covers the whole household.
• Spending the balance every year on routine costs instead of investing it, which forfeits the tax-free growth that makes the account worth having.
• Contributing after enrolling in Medicare, which ends eligibility and makes those contributions excess.
• Confusing an HSA with an FSA — FSA funds are largely use-it-or-lose-it, HSA funds roll over forever.
• Throwing away medical receipts. There's no deadline to reimburse yourself, so a documented expense from years ago can justify a tax-free withdrawal today.

Frequently asked questions

What actually moves this number

Specific levers, and roughly what each one is worth. Not “save more” — the things that change the figure above by an amount you can measure.

• Invest the balance instead of leaving it in cash

  Most HSAs default to a cash account and require a minimum balance before investing is allowed. An HSA left in cash for twenty years is a checking account with paperwork; invested, it is the most tax-advantaged account in the US code.

• Pay current medical costs out of pocket if you can

  Save the receipts. There is no deadline for reimbursing yourself, so a receipt from 2026 can be reimbursed tax-free in 2046 after the balance has compounded for twenty years. Keep them somewhere you will still have them.

• Contribute through payroll, not afterward

  Payroll contributions avoid Social Security and Medicare tax as well as income tax. On the $4,400 self-only limit that is roughly $337 more in your pocket for the same contribution.

• Stop contributing before Medicare enrollment

  HSA contributions must stop once you enroll in Medicare, and Part A enrollment can be backdated up to six months. Contributing into that retroactive window creates an excess contribution and a penalty — plan the last contribution date deliberately.

What this calculator does not cover

Every calculator simplifies, and the useful thing is knowing exactly where. These are the specific gaps between this estimate and your real situation:

• Eligibility requires enrollment in a qualifying high-deductible health plan and no other disqualifying coverage — the calculator assumes you have confirmed that.
• Growth projections assume the balance is invested. Many HSAs hold cash by default and require a minimum balance before investing is permitted.
• Withdrawals for non-qualified expenses before 65 are taxable and carry a 20% penalty; after 65 they are taxable but not penalized.
• Contributions made through payroll also avoid FICA; contributions made directly to the account afterward do not. The calculator does not distinguish them.

For anything that turns on an exact figure, use the primary sources below or a qualified professional. How these limits are decided and disclosed is described in the editorial standards.