Growth Calculator
An HSA is the only account in the US tax code that is tax-free going in, tax-free while it grows, and tax-free coming out. This calculator shows what that's worth: your projected balance in today's dollars, the income tax you avoid on every contribution, and how far ahead you finish versus putting the same money in a taxable brokerage account.
For illustrative purposes only. Not tax, legal, or investment advice.
Updated for 2026 limits: $4,400 individual, $8,750 family.
Results are shown in today's dollars.
Avoids 7.65% FICA tax.
The projection only pays off if you keep the receipts. HSA Monster scans them on-device and tracks exactly how much you can reimburse tax-free — today or thirty years from now. This calculator is built into the app too, already filled in with your real balance, so you can rerun it any time.
Get the free appHow this HSA calculator works
Contributions go in first, then grow
Each year your contribution is added to the balance, and the whole balance compounds at your expected return. Year 0 on the chart is your starting balance before any contribution.
Returns are adjusted for inflation
Your nominal return is converted to a real return with the Fisher equation: real = (1 + nominal) ÷ (1 + inflation) − 1. A 10% return with 2.5% inflation compounds at roughly 7.3%, so the balance you see is in today's purchasing power.
Tax savings use your combined marginal rate
Federal bracket + state income tax + 7.65% FICA (when you contribute through payroll) gives your combined rate. Multiply by your contribution and that's the income tax you never pay — every year you contribute.
The taxable comparison is handicapped honestly
The dashed line invests the same money in a regular brokerage account. It contributes less because it uses after-tax dollars, and its annual gains are reduced by 10% to model the tax owed on dividends and realized gains that an HSA avoids entirely.
2026 HSA contribution limits
To contribute to an HSA you must be covered by a qualifying high-deductible health plan (HDHP) and not enrolled in Medicare. The IRS adjusts the limits every year.
| Coverage type | Annual limit | Age 55+ catch-up |
|---|---|---|
| Self-only (individual) | $4,400 | +$1,000 |
| Family | $8,750 | +$1,000 |
Employer contributions count toward these limits. This calculator does not include the $1,000 age 55+ catch-up.
Why an HSA beats a taxable brokerage account
The gap the calculator shows isn't a return advantage — both accounts earn the same market return. It's a tax advantage, applied at three separate points.
| HSA | Taxable brokerage | Traditional 401(k) | |
|---|---|---|---|
| Money going in | Pre-tax (no FICA via payroll) | After-tax | Pre-tax (FICA still owed) |
| Growth | Never taxed | Dividends & gains taxed | Tax-deferred |
| Money coming out | Tax-free for qualified medical | Capital gains tax | Taxed as ordinary income |
| Required distributions | None | None | Yes |
That's the triple tax advantage. It's also why the strategy only works if you can prove your withdrawals were for qualified medical expenses — which comes down to whether you still have the receipts.
Assumptions and limitations
- Contributions are level. The same amount goes in every year; the calculator doesn't step it up with future IRS limit increases.
- Returns are smooth. Real markets don't return the same percentage annually. A steady rate is a reasonable long-run illustration, not a forecast.
- Contributions land at the start of the year. Each year's contribution is added before that year's growth is applied.
- Your marginal rate stays put. Tax savings use today's combined rate for every year of the projection.
- No fees or HSA cash minimums. Many custodians require a cash balance before you can invest, and charge account or fund fees. Both would reduce these numbers.
- No state-specific HSA quirks. A few states tax HSA contributions or earnings. Set state tax to 0% if yours doesn't offer the deduction.
This tool is an illustration, not advice. Nothing on this page is tax, legal, or investment advice — check with a qualified professional before acting on it.
HSA growth calculator FAQ
How much can I contribute to an HSA in 2026?
For 2026 the IRS limit is $4,400 for self-only HDHP coverage and $8,750 for family coverage. If you're 55 or older the IRS also allows a $1,000 catch-up contribution on top of that, which this calculator does not include.
Are the projected balances in today's dollars?
Yes. The calculator converts your nominal return into a real return using the Fisher equation — real = (1 + nominal) ÷ (1 + inflation) − 1 — so a projected balance 25 years out is expressed in today's purchasing power rather than an inflated future number. Set inflation to 0% if you'd rather see nominal dollars.
Why does the HSA beat the taxable brokerage account?
Three reasons compound together. HSA contributions are made with pre-tax dollars, so more money goes in to begin with. Growth is never taxed, while a taxable account loses a slice of its gains to dividend and capital-gains tax every year. And qualified withdrawals come out tax-free. The comparison line models the taxable account with after-tax contributions and reduces its annual gains by 10% to reflect that ongoing tax drag.
What does the payroll (pre-tax) contribution toggle do?
Contributions made through your employer's payroll deduction avoid Social Security and Medicare tax as well as income tax — 7.65% of FICA on top of your federal and state marginal rates. If you contribute directly to your HSA instead of through payroll, turn the toggle off and the calculator drops FICA from your combined rate.
Do I have to spend my HSA money each year?
No. Unlike an FSA, HSA balances roll over indefinitely and the account is yours even if you change jobs or health plans. That's what makes long-term investing possible — and why many people pay medical costs out of pocket, save the receipts, and reimburse themselves years later. The reimburse later calculator prices out exactly what that patience is worth.
Is this calculator financial advice?
No. It's an illustration built from the assumptions you enter. Real returns vary, tax law changes, and your situation is specific to you. Nothing here is tax, legal, or investment advice — talk to a qualified professional before acting on a projection.
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