Illinois take-home and an 8.2% health cost rise: what an HSA saves

Marsh projects total health benefit cost per employee to rise 8.2% in 2027, the largest rise since 2003 (about 11% without cost-cutting). Applied to a $500/month premium as an illustration, 8.2% is $41 more a month, or $492 a year.

The 8.2% is a total-cost figure, not your paycheck deduction

The 8.2% covers the whole cost per employee, employer and worker shares together. Your own deduction could rise by more or less. The same survey found that about two-thirds of large employers (500+) expect to raise employees' share of premiums, and 59% plan cost-cutting changes such as higher deductibles. So $500 a month rising to $541 is a worked example, not a forecast of your bill.

A health savings account (HSA) also requires a high-deductible health plan, and that plan can carry a different premium than the $500 used here. If you are weighing an HSA-eligible plan, use that plan's own premium and deductible in place of these figures.

What three Illinois households take home: $57,879, $66,941 and $115,760

These figures use 2026 federal income tax, Social Security and Medicare tax (FICA) and Illinois income tax, with the standard deduction and no other deductions or credits. Local, sales and property taxes are left out. Open enrollment is for 2027, and 2027 brackets and the standard deduction may differ, so treat the dollar amounts as a close guide rather than your 2027 result. The $75,000 earner files as single. The other two are married, and the $150,000 household is a dual-income couple with $150,000 combined. Illinois's median household income in the LifeCalc dataset is $83,211, so the $83,000 couple sits at the median.

Household	Take-home a year	Per month	Effective tax rate
Single, $75,000	$57,879	$4,823	22.8%
Married, $83,000	$66,941	$5,578	19.3%
Married, $150,000	$115,760	$9,647	22.8%

A $500/month premium is $6,000 a year, and after an 8.2% rise it is $6,492. That is 11.2% of the single earner's take-home and 9.7% of the $83,000 couple's. This treats the premium as paid from after-tax pay. Many employer premiums come out before tax, which would make the share of take-home somewhat smaller. Run your own salary through the paycheck calculator to see your figures.

A $4,500 HSA saves the $83,000 couple $763 in income tax

Contributions made through your paycheck lower your taxable income. For the $83,000 couple, $4,500 saves $540 in federal tax and $223 in Illinois tax, $763 in all. The net cost of that contribution is $3,737.

That $763 should not be read against the $492. The $492 is a cost you may be handed. The $3,737 is money you move into your own account by choice, and it only pays off if you spend it on medical costs. The tax saving makes each dollar you set aside cheaper. It does not cancel a premium increase. These savings count income tax only. FICA savings, which can apply to HSA payroll contributions, are not included.

Doubling to $9,000 roughly doubles the tax saved, and the net cost

The $4,500 and $9,000 amounts are illustrations, not IRS limits. No limit is in the verified figures here, and limits differ for self-only and family coverage, so confirm the current ones with your plan or the IRS before you elect.

Household	Contribution	Income tax saved	Net cost
Single, $75,000	$4,500	$1,213	$3,287
Married, $83,000	$4,500	$763	$3,737
Married, $83,000	$9,000	$1,526	$7,474
Married, $150,000	$4,500	$1,213	$3,287
Married, $150,000	$9,000	$2,425	$6,575

At $83,000, going from $4,500 to $9,000 moves the tax saved from $763 to $1,526 and the net cost from $3,737 to $7,474. At $150,000 the $9,000 contribution saves $2,425 and costs $6,575 net.

A rule for what to set aside at open enrollment

1. Confirm eligibility first. Without a qualifying high-deductible plan, none of the savings above apply.
2. Find your likely medical spending. Start from the plan's deductible and the costs you expect, not from the tax saving.
3. Set the contribution near that spending if the monthly cash flow allows. The net costs in the table, from $3,287 to $7,474, come out of take-home of $4,823 to $9,647 a month, so check the deduction against your fixed bills first.
4. Stay under the IRS limit for your coverage type. Confirm it before you elect.

If you would rather keep cash free for rent and groceries than prepay medical costs, the numbers point to a smaller contribution, since every dollar still lowers taxable income by that dollar. If you expect to hit your deductible anyway, a larger contribution turns costs you would pay anyway into pre-tax dollars.

What would change this

• Your actual premium. If your employer shifts more than 8.2% to you, the increase is larger than $492. If your HSA-eligible plan has a different premium, it may differ either way.
• Your deductible. With 59% of employers planning changes such as higher deductibles, what you owe before insurance pays may matter as much as the premium.
• Your tax situation. The same $4,500 saves $1,213 for the single earner and $763 for the $83,000 couple.
• 2027 tax rules. These figures use 2026 rules.

To test a deduction against your monthly spending, use the budget calculator, and for your own tax picture, the tax calculator. Method notes are on the methodology page.