How to Determine Your HSA Contribution: Limits, Eligibility, and Fixes

For 2026, the HSA contribution limits are $4,400 if you have self-only high-deductible health plan (HDHP) coverage and $8,750 if you have family coverage, with an extra $1,000 catch-up available once you turn 55. Those ceilings assume you were eligible every month of the year and count every dollar your employer puts in alongside your own. Miss a month of eligibility, take employer contributions, or enroll in Medicare partway through the year, and your personal ceiling drops. Overshoot the real number and a 6% excise tax hits the excess every year it stays in the account.¹

The 2026 Dollar Amounts

Three numbers govern how much you can put in for the year, assuming full-year eligibility:²

Self-only HDHP coverage: $4,400
Family HDHP coverage: $8,750
Catch-up contribution at age 55 or older: an additional $1,000

Self-only versus family depends on whether your HDHP covers only you or at least one other person. The $1,000 catch-up is set by statute and doesn’t index for inflation, which is why it hasn’t changed in years. If you and your spouse are both 55 or older, you can’t stack both catch-ups into a single account. Each spouse needs an HSA in their own name to claim their own $1,000.³

Every dollar going into the account counts against the limit. That includes your payroll contributions, direct deposits you make yourself, employer contributions, and anything a third party puts in on your behalf. If your employer deposits $2,000 into your HSA and you have self-only coverage, your remaining room for personal contributions is $2,400, not $4,400.⁴

Who Is Eligible to Contribute

You can contribute for any month where, on the first day of that month, all of the following are true:⁵

You’re enrolled in an HDHP. For 2026, that means a minimum annual deductible of $1,700 (self-only) or $3,400 (family), with out-of-pocket costs capped at $8,500 or $17,000.²
You have no other health coverage that pays benefits before you meet the HDHP deductible. A general-purpose FSA or a spouse’s non-HDHP plan disqualifies you. A limited-purpose FSA that reimburses only dental and vision expenses is fine.
You’re not enrolled in any part of Medicare. Starting the first month you’re enrolled, your contribution limit for that month is zero.⁶
Nobody else claims you as a dependent on their tax return.⁵

The Medicare rule trips up people turning 65. If you claim Social Security in that year, you’re automatically enrolled in Medicare Part A, and Part A can apply retroactively for up to six months. Contributions made during those retroactive months become excess contributions. To keep contributing past 65, you generally have to delay both Medicare and Social Security.⁶

What Changed for 2026

The One Big Beautiful Bill Act widened HSA eligibility starting January 1, 2026. Bronze and catastrophic plans sold on the health insurance marketplace now count as HSA-compatible, whether or not they meet the traditional HDHP deductible and cost-sharing rules. The IRS has said this treatment applies even to bronze and catastrophic plans bought outside the marketplace.⁷

Direct primary care arrangements no longer block HSA contributions. Paying a monthly fee to a DPC provider is now compatible with an HSA, and you can pay those fees with HSA dollars tax-free.⁷ The law also made permanent the pre-deductible telehealth allowance that had rolled forward on temporary extensions since the pandemic.

Prorating for Partial-Year Coverage

If you weren’t eligible for all 12 months, the default calculation is to divide the annual limit by 12 and multiply by the number of months you were eligible on the first of the month. Someone with self-only coverage who enrolled June 1 is eligible for seven months, so their base limit is $4,400 × 7/12, or roughly $2,567.

The Last-Month Rule

There’s a shortcut. If you’re eligible on December 1, the IRS lets you contribute the full annual limit as though you’d been eligible all year.⁶

The catch is a 13-month testing period running from December 1 of the contribution year through December 31 of the following year. Lose eligibility at any point in that window and the amount you contributed above your prorated share gets added to your taxable income, with an extra 10% tax on top. Death or disability during the testing period is an exception; in those cases the full-year contribution stands without the recapture.⁵

How the Money Gets In

Two paths lead into the account, and the tax result differs. Payroll contributions run through your employer’s Section 125 cafeteria plan and come out before federal income tax, Social Security tax, and Medicare tax are calculated. That’s the more efficient route because you avoid FICA on those dollars entirely.⁸

Direct contributions through your provider’s portal or by check use after-tax dollars. You claim the deduction on Form 8889, and it flows to Schedule 1 (Form 1040), line 13, cutting your adjusted gross income.⁹ You have until the tax filing deadline of the following year to make contributions counted toward the prior tax year, so 2026 contributions can be made through April 15, 2027. Married couples with separate HSAs each file their own Form 8889 and combine the deductions on a joint return.

Fixing an Overage Before the Penalty Hits

Going over the limit isn’t automatically a 6% problem. Withdraw the excess along with the earnings it generated inside the account by your tax filing deadline (including extensions), and the IRS treats the contribution as though it never happened. You don’t deduct the withdrawn amount, and you report the earnings as income on that year’s return.⁹

If you already filed without catching the excess, you have a further window. Withdraw the money within six months of the original due date of your return (not counting extensions) and file an amended return with “Filed pursuant to section 301.9100-2” at the top.⁹

Miss both deadlines and the 6% excise tax applies, reported on Form 5329. The tax keeps recurring every year until you either take the excess out or absorb it by contributing less than your limit in a future year.¹⁰

1
Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts and Annuities
2
IRS. Notice 2026-05 – Expanded Availability of Health Savings Accounts Under the OBBBA
3
Internal Revenue Service. HSA Contributions – IRS Courseware – Link and Learn Taxes
4
Internal Revenue Service. HSA Contributions – IRS Courseware – Link and Learn Taxes
5
Office of the Law Revision Counsel. 26 USC 223 – Health Savings Accounts
6
Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans
7
Internal Revenue Service. Treasury, IRS Provide Guidance on New Tax Benefits for Health Savings Account Participants Under the One Big Beautiful Bill
8
Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans
9
Internal Revenue Service. Instructions for Form 8889 (2025)
10
Internal Revenue Service. Instructions for Form 5329 (2025)