A good working answer: keep at least your health plan’s annual deductible in cash inside your HSA, and invest anything above that. If you want a bigger cushion against a bad medical year, hold your out-of-pocket maximum in cash instead. Everything above that line is money you don’t need liquid, and leaving it in cash wastes the account’s biggest advantage. For 2026, the ceiling on what you can put in is $4,400 for self-only coverage and $8,750 for family coverage, plus a $1,000 catch-up if you’re 55 or older.1IRS.gov. Expanded Availability of Health Savings Accounts Under the One, Big, Beautiful Bill Act How much of that limit to actually contribute, and how to split what’s already in the account, comes down to two numbers in your plan documents.
Start With the Two Numbers in Your Plan
Pull out your Summary of Benefits and Coverage, the standardized document your insurer provides each plan year. Two figures do most of the work.
Your annual deductible is what you pay before the plan starts sharing costs. Treat this as the floor for your HSA cash balance. If you can’t cover the deductible from the account, you’ll end up paying medical bills from your checking account and losing the tax advantage that makes the HSA worth having in the first place.
Your out-of-pocket maximum is the ceiling on what you’ll spend in a plan year on covered services, including copays and coinsurance. Holding this amount in cash means even a major surgery or hospital stay won’t force you into debt or into selling investments at a bad time. For 2026, the federal cap on out-of-pocket maximums for HSA-eligible plans is $8,500 for individuals and $17,000 for families, though your plan’s actual number is often lower.1IRS.gov. Expanded Availability of Health Savings Accounts Under the One, Big, Beautiful Bill Act
If you’re generally healthy and have other savings you could tap in an emergency, aiming for the deductible is reasonable. If you want genuine peace of mind against a bad year, target the out-of-pocket max. Either way, this is the money you keep in cash, not invested, because you might need it fast.
How to Split Cash and Investments
Most HSA providers let you invest your balance once it crosses a threshold, commonly $1,000 or $2,000. The invested portion can go into mutual funds, index funds, or ETFs, depending on your provider’s menu. Growth is completely tax-free as long as you eventually use the money for qualified medical expenses.
So the practical rule of thumb:
- Cash portion: at least your deductible, up to your out-of-pocket maximum if you want more safety.
- Invested portion: everything else.
The right split depends on how stable your health is, what other emergency savings you have, and how soon you might realistically need the money. A single person with strong cash reserves elsewhere can lean toward the deductible-only floor. A family with three kids and a tight budget outside the HSA is better off carrying the out-of-pocket max.
Where most people go wrong is leaving everything in cash for years. An uninvested HSA sitting in a low-interest cash account is just a tax-free savings account. That’s fine, but it leaves the most powerful feature of the account unused. The real wealth-building happens when you invest the balance and let it compound for decades without ever paying taxes on the growth.
How Much You’re Allowed to Contribute in 2026
The IRS adjusts HSA contribution limits annually for inflation. For 2026:
- Self-only coverage: $4,400
- Family coverage: $8,750
- Catch-up contribution (age 55 or older): an additional $1,000
These limits apply to the combined total of what you and your employer put in.1IRS.gov. Expanded Availability of Health Savings Accounts Under the One, Big, Beautiful Bill Act If your employer contributes $1,500 toward your family HSA, your personal cap drops to $7,250.2Internal Revenue Service. HSA Contributions This trips people up more than almost anything else with HSAs. Check your most recent pay stub or benefits portal to see how much your employer is kicking in before you set your own contribution.
The catch-up amount is fixed at $1,000 by statute and doesn’t adjust for inflation.3Internal Revenue Service. HSA Limits on Contributions If both you and your spouse are 55 or older, you can each contribute an extra $1,000, but you need separate HSAs to do it. Only contributions made in cash count; you can’t transfer stock or other property into the account.4Office of the Law Revision Counsel. 26 USC 223 – Health Savings Accounts
You can also contribute for the prior tax year up until the April filing deadline. Contributions made by April 15, 2026, for example, can count toward your 2025 limit if you haven’t maxed it out yet.5Internal Revenue Service. Instructions for Form 8889 (2025)
If you contribute above your annual limit, the excess amount gets hit with a 6% excise tax every year it stays in the account.6Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts and Annuities You can avoid the penalty entirely by withdrawing the excess (plus any earnings on it) before your tax filing deadline, including extensions. The withdrawn earnings get reported as income on your return for the year of the withdrawal.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans This most often happens when people change jobs and contribute to two employer HSAs in the same year, or forget to count their employer’s contribution against the annual cap.
Why Contributing More Than You Spend Is the Point
An HSA offers a triple tax benefit that no other account matches: contributions reduce your taxable income, growth is tax-free, and withdrawals for qualified medical expenses are tax-free. A 401(k) taxes you on the way out. A Roth IRA taxes you on the way in. The HSA, used for medical costs, taxes you at no point.
That structure rewards a specific strategy: pay current medical bills out of pocket if you can afford to, keep every receipt, let the HSA balance grow invested for years, and then reimburse yourself in a lump sum whenever you want. The IRS has no deadline for when you claim reimbursement, as long as the expense was incurred after the HSA was established.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans You could pay a $3,000 dental bill in 2026 and reimburse yourself tax-free in 2041.
This only works if your records are solid. The IRS requires documentation showing that each distribution went toward a qualified medical expense, that the expense wasn’t reimbursed from another source, and that you didn’t claim it as an itemized deduction.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans A dated folder of receipts and explanation-of-benefits statements is the minimum. Don’t rely on your HSA provider to keep records for you; account statements won’t show what the money was actually spent on.
Watch the Edges: Before 65, at 65, and Medicare
Before you turn 65, withdrawing HSA money for anything other than a qualified medical expense costs you income tax plus a 20% additional tax on top.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans That’s double the 10% early-withdrawal penalty on traditional IRAs.8Office of the Law Revision Counsel. 26 USC 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts So the “invest everything above your deductible” advice has a corollary: don’t invest money you might be tempted to raid for non-medical reasons before 65.
After 65, non-medical withdrawals are taxed as ordinary income but face no additional penalty. At that point the HSA functions much like a traditional IRA, with medical withdrawals still tax-free on top.
Starting the first month you enroll in Medicare, your HSA contribution limit drops to zero.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans You can still use and invest the money already in the account, but you can’t add more. Medicare Part A enrollment is sometimes backdated up to six months when you sign up after 65; if that happens, any HSA contributions made during the retroactive coverage period become excess contributions subject to the 6% excise tax. If you’re approaching 65 and still working, work out the timing with your benefits administrator before enrolling.
Adjusting What You Put In Through the Year
Unlike a flexible spending account, which generally locks you into an annual election, HSA payroll contributions can typically be changed at any point during the year. Check with HR or your benefits portal for the process; most employers update the deduction within one or two pay cycles.
If you hold an HSA independent of an employer, you can make direct contributions through a bank transfer or check deposit whenever you want. This is useful late in the year if you realize you haven’t hit the maximum, and remember that contributions made by April 15 of the following year can still count toward the prior year’s limit.5Internal Revenue Service. Instructions for Form 8889 (2025)
The most common adjustment mistake is increasing your contribution without checking whether your employer’s share already pushes you close to the limit. If your employer adds $2,000 and you contribute $6,750 on a family plan, you’re at $8,750 exactly, and one extra dollar creates an excess contribution. Track both sides of the contribution throughout the year rather than setting it once and forgetting it.