HSA rules for 2026: limits, the HDHP test and the triple tax break

A health savings account is the one account in the tax code that can be tax-free on the way in, while it grows, and on the way out. That is why people call it the triple tax break. It also has more entry rules than most accounts, and a couple of traps that only show up at tax time. This page walks through who can contribute in 2026, how much, the plan that has to sit underneath it, the December rule, and what happens if the money comes out for something other than medical care.

Who can contribute: the eligible individual

You can only put money into an HSA for a month in which you are an "eligible individual." ³ For each month, that means:

• You are covered by a high deductible health plan (HDHP) on the first day of the month.
• You have no other health coverage that isn't on the allowed list. Coverage such as dental, vision and accident insurance is disregarded. ²
• You are not enrolled in Medicare. From the first month you are enrolled, your contribution limit is zero. ³
• No one else can claim you as a dependent. ³

Notice what is missing from the list: income. There is no income limit on HSA contributions. The gate is your health coverage, month by month.

What counts as a high deductible health plan in 2026

The plan has to clear two bars for 2026: a deductible that is high enough, and an out-of-pocket maximum that is low enough. ¹

Your insurer or employer usually labels a plan "HSA-eligible," but the label is a promise, not a rule. If you are unsure, these two lines are the test.

The 2026 contribution limits

^{1 2}

Three details that trip people up:

1. The limit is shared. Your employer's contributions, including pre-tax payroll contributions through a cafeteria plan, count toward the same limit as yours. ³
2. It is figured month by month. The law sets the limit as a monthly amount, one twelfth of the annual figure for each month you are eligible, unless the December rule below applies. ²
3. Married couples share the family limit. If either spouse has family HDHP coverage, both are treated as having family coverage, and the limit is split between them equally unless they agree on a different split. The catch-up belongs to each person and goes into that person's own HSA. ²

You have until the regular filing deadline to contribute for a year. Contributions for 2025 could be made through April 15, 2026, and the same pattern applies to 2026 contributions. ³

The triple tax break

Here is why the account earns its reputation.

• In. Contributions you make yourself are deductible on your return even if you don't itemize, and employer contributions are left out of your income. ^{2 3}
• While it grows. The account itself is exempt from tax, so interest and investment growth aren't taxed each year. ²
• Out. Withdrawals used for qualified medical expenses are not included in income. ²

Unspent money is not lost at year end. The balance carries over, year after year. ³ The account is yours, not your employer's, so it stays with you when you change jobs.

The December rule and its testing period

There is a shortcut called the last-month rule. If you are an eligible individual on December 1, you are treated as eligible for the whole year, so you can contribute the full annual amount even if your HDHP coverage started late in the year. ³

The shortcut comes with a string attached: a testing period. You must stay an eligible individual from December of that year through the end of the 12th month after it. ³ If you drop out early for a reason other than death or disability, the part of your contribution that you could only make because of the last-month rule is added to your income for the year you drop out, plus an additional tax on that amount. ³ Starting a job with non-HDHP coverage, or enrolling in Medicare, partway through the testing period are the usual ways it happens.

Withdrawals that aren't for medical care

Take money out for something other than qualified medical expenses and two things happen: the withdrawal is included in your income, and an additional tax of 20% of it applies on top. ^{2 3}

The additional tax goes away after you become disabled, after death, or once you reach the age of Medicare eligibility; Publication 969 puts it as no additional tax after you "reach age 65." ³ The income tax on a non-medical withdrawal still applies at that point, so after that age the account can work much like a traditional IRA for non-medical spending, and stays tax-free for medical spending.

Keep your receipts. The tax-free treatment depends on the withdrawal matching a qualified medical expense, and the record of that is yours to keep.

Form 8889: the form that comes with the account

Form 8889 goes with your Form 1040 for any year in which you, your employer or anyone else contributed to your HSA, the HSA made a distribution, you failed the testing period, or you inherited an interest in an HSA. ⁴ Employer contributions show on your Form W-2 in box 12 with code W. ³ Even a year with only employer money in and nothing out still needs the form.