See how 401(k) and HSA contributions move your take-home.
Covers: paycheck, optimizer, 401k, hsa, pre-tax, take home, tax savings.
Open the Paycheck Optimizer tool →Pre-tax contributions lower your tax bill, but not all of them the same way. A traditional 401(k) deferral cuts your income tax. An HSA contribution through payroll cuts your income tax too, and it also skips Social Security and Medicare (FICA) tax, so each dollar saves a little more. This shows your take-home now and the tax saved by the next $1,000 into each, using the same federal + FICA + state engine as the take-home tile — including, in Maryland and Indiana, the county income tax every resident pays, since a dollar moved into the 401(k) escapes that too. Optional local taxes you would have to opt into (New York City, Yonkers, Columbus, Detroit) are not included here.
The figures are exact for the numbers you enter. HSA money is meant for medical costs and needs an HSA-eligible health plan, so it isn't a free lunch, but if you have one, it's the most tax-efficient dollar on your paycheck. Filing status, state, and income flow to and from My Situation. To tune the W-4 itself against your actual paycheck withholding, use the W-4 Withholding & Refund Check.
Five deductions new for 2026 are not modeled here: tips (§224), overtime (§225), car loan interest (§163(h)(4)), the deduction at 65 (§151(d)(5)(C)), and giving without itemizing (§170(p)). If any of them applies to you, your real federal tax is lower than the figure above. Take-Home and Federal Income Tax ask for them and apply them.
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