Compare matching tax bases before comparing rates. This annual model separates federal brackets, a flat state proxy, payroll and cash deposits. Next-dollar and next-$1,000 figures recalculate one ledger rather than assuming a federal bracket describes every tax.

Brackets are marginal, not total

For a 2026 single filer with $100,000 wages and no deposits, $16,100 standard deduction leaves $83,900 taxable. Tax is $1,240 + $4,560 + $7,370 = $13,170, or 13.17% of gross. The next taxable dollar is in the 22.00% band. Payroll adds $7,650: combined effective 20.82% and spendable cash $79,180. All these distinct measures come from one receipt.

How to calculate your effective rate

Eligible traditional retirement deposits reduce federal income but remain in employee payroll wages. Eligible cafeteria health/HSA elections reduce those wages; direct HSA or SE health deductions do not. SE mode deducts half regular SE tax and limits income-tax adjustments to available earnings. Every deposit still reduces cash. Eligibility and remaining contribution room must be established separately.

The bracket myth: will a raise cost me money?

Aged/blind standard additions and enhanced senior deductions are separate. One confirmed eligible single person age 65 earning $100,000 in 2026 has $16,100 + $2,050 standard and $4,500 enhanced deduction: taxable $77,350, federal tax $11,729. Add excluded Puerto Rico and Form 2555/4563 amounts to senior MAGI where applicable. MFS cannot claim the enhanced deduction. This is not a complete couple return.

Marginal for decisions, effective for budgeting

Use the keyboard comparison field or select a chart point with contribution dollars and policy fixed. Incomes that cannot fund deposits are unavailable. Save A/B for a same-year delta; previous scenarios remain labeled when current inputs change. Allocation retains signed cash and reconciles gross. At zero gross percentages are not applicable. Rounded displays may differ slightly from exact totals.

What this calculator does and doesn't model

Credits, QBI, AMT, NIIT, capital gains, local taxes, contribution eligibility and a full return are excluded. Blank state means not modeled; entered zero is explicit. This is annual liability, not withholding. Inputs and A/B stay in browser storage; Clear saved scenarios removes A/B. Sharing defaults to year/view only. Review fields before opting into a full link. CSV, copy and print disclose financial facts, so store them privately.