Tools · Paycheck Optimizer
Maxing your 401(k)
costs less than you think.
Pre-tax contributions reduce your taxable income. Enter your salary and see exactly what maximizing each account does to your actual take-home pay.
This page covers US-specific accounts and tax law. Outside the US? The priority order is the same, the account names differ (ISA in the UK, TFSA/RRSP in Canada, Super in Australia, etc.).
// VERIFY NUMBERS
FICA caps, federal-tax brackets, and 401(k)/HSA contribution limits update every January. Figures baked into this tool reflect the year noted in the source; verify the current year's numbers at irs.gov and ssa.gov before treating a result as final.
CURRENT ELECTIONS ($/YEAR)
OPTIMIZE TO 2026 MAX verify×DON'T TRUST, VERIFYClaim: 2026 contribution limits: 401(k) $24,500, HSA $4,400/$8,750, FSA $3,300.Verify at: IRS limit announcements ↗Indexed annually for inflation.
KEY INSIGHT
CURRENT SETUP
OPTIMIZED SETUP
FICA note: Social Security and Medicare taxes (FICA, 7.65% combined employee share) apply to your full gross salary regardless of pre-tax contributions. 401(k) and HSA contributions reduce federal and state income tax but not FICA verify×DON'T TRUST, VERIFYClaim: FICA is 7.65% employee share (6.2% SS + 1.45% Medicare). HSA via payroll avoids FICA; 401(k) does not.Verify at: IRS Topic 751 ↗Social Security tax applies up to the annual wage base; Medicare has no cap..
What this tool assumes
- Federal withholding estimated from the W-4 methodology; actual withheld may differ.
- FICA at 7.65% applies to wages up to the Social Security wage base ($184,500 in 2026).
- State tax estimated using single-filer graduated brackets where applicable.
Not financial advice. Rough estimates for standard deduction filers. Actual tax situations vary.