Start with what you can afford to lose to medical expenses

The amount you put into your HSA should match the medical costs you actually expect to pay out of pocket in the next year, plus a buffer for surprises. This is not about maxing out the account just because you can. If you contribute more than you will spend, that money sits there until you need it — which is fine for long-term savings, but it means less money in your regular paycheck right now.

Begin by looking at last year's medical bills: copays, deductibles you hit, prescriptions, dental work, vision care, therapy sessions. Add up what you paid out of pocket. That number is your baseline. Then ask yourself whether this year will be similar or different. Are you planning surgery? Starting a new medication? Switching to a plan with a higher deductible? Those changes move your number up.

The IRS sets annual contribution limits, which vary by year. For 2024, the limit is $4,150 for individual coverage and $8,300 for family coverage. You cannot contribute more than that, and you cannot contribute more than your household earned in income. But hitting the limit does not mean you should — it means that is the ceiling, not the target.

Key Takeaways

  • Contribute only what you expect to spend on medical costs in the next 12 months, because money you do not use stays locked in the account until you need it.
  • Review your actual out-of-pocket medical spending from the past year to set a realistic number for the year ahead.
  • Account for changes: a new deductible, planned procedures, new prescriptions, or life events that affect your health spending.
  • If you have a spouse and both work, you can each open an HSA and contribute separately, so coordinate your household total to avoid overfunding.
  • You can adjust your contribution amount once per year during open enrollment, or immediately if you have a may have access to life event.

How your deductible shapes your contribution

Your health plan's deductible is the biggest driver of how much you should contribute. If your deductible is $1,500, you will likely pay at least that much out of pocket before insurance kicks in — so $1,500 is a floor for your HSA contribution. If your deductible is $5,000, your floor is higher.

But the deductible is not the only out-of-pocket cost. After you meet the deductible, you still pay copays (fixed amounts per visit) and coinsurance (a percentage of the bill). Add those up too. If you see a therapist monthly at a $30 copay, that is $360 per year. If you take a prescription with a $50 monthly copay, that is $600 per year. These add up fast.

Some plans also have an out-of-pocket maximum — the most you will pay in a year before insurance covers everything. If your out-of-pocket maximum is $3,000, you know that in a worst-case year, you will need $3,000 in the HSA. In a typical year, you will need less. A reasonable contribution is somewhere between your deductible and your out-of-pocket maximum.

Account for predictable medical spending you know is coming

If you know you will have a specific medical event this year, add that cost to your baseline. A planned surgery, a course of physical therapy, dental work, or a procedure your doctor has already scheduled should all be factored in. Call your provider's billing department or check your insurance's cost estimator tool to get a rough number.

The same applies to prescriptions you take regularly. If you refill a medication 12 times per year and each refill costs $25 after insurance, that is $300 you know you will spend. If you wear glasses or contacts and need a new prescription, add that cost. If you get allergy shots or regular injections, include those too.

Pregnancy and childbirth are major expenses. If you are planning to have a baby this year, your out-of-pocket costs could be anywhere from $1,000 to $5,000 or more, depending on your plan and whether complications arise. Talk to your OB's billing office about what your plan will charge.

Decide whether to save for future years or just cover this year

An HSA is one of the few accounts that lets you save money year after year without losing it. Unlike a flexible spending account (FSA), which empties at the end of the year, an HSA balance rolls forward forever. This means you can contribute more than you need this year and let the extra sit there for future medical costs or retirement.

This strategy makes sense if you are healthy now and want to build a cushion for later. Contribute what you will spend this year, then add a little extra — maybe $500 or $1,000 — to cover unexpected costs or to start building a long-term reserve. Over time, this becomes a powerful retirement savings tool, because you can withdraw money tax-free for medical expenses at any age.

But if you are tight on cash right now, do not over-contribute just for the tax break. Contribute what you need for this year's medical costs, and leave it at that. You can always add more next year during open enrollment.

Coordinate with your spouse if you both have HSA-may be able to access plans

If you are married and both work, you each have the option to open your own HSA — but you cannot both contribute the family limit. The family limit applies to your household as a whole. If you are both on family plans through your employers, you need to coordinate so your combined contributions do not exceed the annual limit.

One common approach: one spouse contributes through their employer, and the other does not. Another approach: you split the family limit between you. Talk to both employers' benefits departments to understand how they handle this, because the rules can vary.

If you are on a family plan through one employer and your spouse is on an individual plan through another, the rules are different — check with both plans' administrators before you contribute.

Adjust your contribution if your plan or life changes

You can change your HSA contribution amount once per year during open enrollment, which usually happens in the fall. But if you have a may have access to life event — you get married, have a baby, lose coverage, or change jobs — you can adjust your contribution immediately, outside of open enrollment.

If you switch to a plan with a higher deductible, increase your contribution. If you switch to a plan with a lower deductible, you can lower your contribution. If you retire or lose HSA-may be able to access coverage, you stop contributing, but the money already in your account stays there and you can still use it for medical expenses.

Keep your employer's benefits team in the loop about any changes. They manage the payroll deduction, and they need to know if you want to adjust the amount.

Frequently Asked Questions

What happens if I contribute too much to my HSA?

The money does not disappear — it stays in your account and rolls over to next year. You can use it for medical expenses anytime in the future, even decades later. The only penalty is if you contribute more than the IRS limit; in that case, you owe taxes and a 6% penalty on the excess amount. Contact your HSA provider to withdraw the overage before tax time.

Can I contribute a lump sum at the beginning of the year instead of payroll deductions?

Yes. If your employer does not offer HSA contributions through payroll, or if you are self-employed, you can open an HSA with a bank or investment company and contribute directly. You have until tax day of the following year to make contributions for the current year. Payroll deductions are simpler because the money comes out before taxes, but direct contributions work too.

Should I contribute the maximum just for the tax deduction?

Only if you actually expect to spend that money on medical costs. The tax break is real, but it is not worth locking up money you will not use. If you have extra cash and want to save for future medical expenses or retirement, then yes, contribute more. But if you need that money for other bills, contribute only what you will spend this year.

What if I do not use all my HSA money by the end of the year?

Unlike an FSA, your HSA balance carries over. You can use it next year or any year after that. There is no deadline to spend it. This makes an HSA a good long-term savings vehicle if you stay healthy and do not need the money right away.

Can I change my contribution amount mid-year?

Only if you have a may have access to life event: marriage, divorce, birth of a child, loss of coverage, or a change in employment. Open enrollment is the standard time to adjust, which happens once per year. If your situation changes, contact your employer's benefits team to see if you may have access to for a mid-year change.