HSA Contribution Limit Calculator (2026 & 2027)

For 2026 it is $4,400 with self-only coverage and $8,750 with family coverage (Rev. Proc. 2025-19). For 2027 it is $4,500 and $9,000 (Rev. Proc. 2026-24). Anyone who reaches 55 before the end of the year can add $1,000. The limit covers everything that goes in: your own money, your employer's (payroll deductions through a cafeteria plan count as employer money) and anyone else's.

For 2027 a plan is a high-deductible health plan if its deductible is at least $1,750 (self-only) or $3,500 (family) and its out-of-pocket maximum is no more than $8,700 or $17,400. For 2026 the figures are $1,700 and $3,400, and $8,500 and $17,000 (Rev. Proc. 2025-19).

Each month in which you are covered by an HDHP on the 1st (and have no disqualifying other coverage, and are not on Medicare) earns one twelfth of the self-only or family amount, depending on your coverage that month. The twelfths add up (26 U.S.C. 223(b)(1)-(2); Form 8889 Line 3 Limitation Chart). Medicare entitlement sets the limit to zero from its first month, and the age-55 catch-up is prorated the same way. Example from Publication 969: turned 65 in July, self-only, with the catch-up: $5,300 × 6 ÷ 12 = $2,650(2025 amounts).

The last-month rule is the exception. If you are covered on December 1, you can treat yourself as eligible for the whole year, with the coverage you had on December 1 (223(b)(8)). A person who starts self-only coverage in March 2026 gets $4,400, not the $3,667 that ten months would give.

Using the last-month rule means you must stay eligible from December 1 of that year through December 31 of the next (for most people, 13 months). If you stop being an eligible individual in that time, other than because of death or disability, the contributions that were possible only because of the rule become income in the year you fail, plus a 10% additional tax (223(b)(8)(B); Form 8889 Part III).

Publication 969's examples, with the 2025 amounts: family coverage first held on December 1 and $8,550 contributed; eligibility lost in June 2026. The limit without the rule is $713, so $7,838 is added to 2026 income. In the second example (self-only until November 1, then family; eligibility lost in March 2026) the limit without the rule is $5,008, so $3,542 is added.

Your limit is zero from the first month you are entitled to Medicare (223(b)(7)). Premium-free Part A starts up to 6 months before the month you sign up for it or apply for Social Security benefits, but never before the month you turn 65 (Medicare.gov; 42 CFR 406.6(d)(4)), and Publication 969 says contributions made for the months of retroactive coverage are excess contributions. Medicare.gov's advice is to stop contributing 6 months before you retire or apply for Social Security.

The “When does my Medicare start?” box in the calculator turns a birth month and the month you apply into the Part A start and the last month a contribution counts. Because the last-month rule needs you to be eligible on December 1, it does not help in the year Medicare starts.

If you are married and either of you has family HDHP coverage, you are both treated as having the family coverage, and if you are both eligible there is one family limit for the two of you, divided equally unless you agree on a different split (223(b)(5)). Each spouse who is 55 or older adds their own $1,000 to their own HSA, so two spouses over 55 can put in $10,550 together with the 2025 amounts (Publication 969). If your spouse is on Medicare, they are not an eligible individual and the whole family limit is yours. If your spouse has a separate, non-HDHP plan that does not cover you, you can still be eligible.

Yes. What your employer puts in (Form W-2 box 12, code W, including your paycheck deductions through a cafeteria plan) and any one-time IRA-to-HSA transfer reduce the amount you can add yourself (223(b)(4); Form 8889 lines 8-12). Archer MSA payments reduce it too. Employer money above the limit is taxable to you if the W-2 does not already include it.

You can contribute for a tax year until the unextended due date of the return for that year (April 15 of the next year for most people). The excess is charged a 6% excise tax for each year it stays in the account (Form 5329). You can avoid it by withdrawing the excess, and any income it earned, by the due date of the return including extensions; the earnings are taxed as other income (Form 8889 instructions, line 13).