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 (ISAIndividual Savings Account (ISA)A UK tax-advantaged account where contributions are post-tax but all growth and withdrawals are tax-free.Full definition in the UK, TFSATax-Free Savings Account (TFSA)A Canadian tax-advantaged account where contributions are post-tax but all growth and withdrawals are tax-free.Full definition/RRSPRegistered Retirement Savings Plan (RRSP)A Canadian tax-deferred retirement account; contributions reduce taxable income and growth is tax-deferred until withdrawal.Full definition in Canada, Super in Australia, etc.).
// VERIFY NUMBERS FICAFederal Insurance Contributions Act (FICA)The payroll tax that funds Social Security and Medicare, split between employee and employer.Full definition caps, federal-tax brackets, and 401(k)/HSAHealth Savings Account (HSA)A tax-advantaged account for healthcare costs, available with a high-deductible plan; contributions, growth, and qualified withdrawals are all tax-free.Full definition 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 ×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 ×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 deductionstandard deductionA fixed dollar amount that reduces your taxable income without itemizing. Most people claim this instead of listing individual deductions.Full definition filers. Actual tax situations vary.

Related

→ Tax Estimator, the full 2026 federal + all-50-state engine → Cost of Living Calculator, see what your real monthly costs are → Personal Finance Order of Operations → Roth vs Traditional → HSA Calculator