Methodology

This page explains exactly how PaycheckSimple estimates your take-home pay for the 2025 tax year, so you can judge its accuracy and limitations.

1. Annualizing your pay

We first convert your input into an annual gross figure based on your pay frequency (weekly × 52, bi-weekly × 26, semi-monthly × 24, monthly × 12, or annual × 1). All taxes are computed annually, then divided back down to a per-paycheck amount.

2. Federal income tax

We subtract the standard deduction for your filing status, then apply the 2025 progressive federal brackets marginally — each portion of income is taxed at its bracket's rate. We do not model itemized deductions, pre-tax retirement contributions, or tax credits.

3. FICA — Social Security & Medicare

• Social Security: 6.2% of wages up to the annual wage base limit.
• Medicare: 1.45% of all wages, plus an additional 0.9% on wages above the filing-status threshold.

4. State income tax

Each state is modeled as a config object with one of three types: none (no state income tax), flat (single rate), or progressive (brackets). All 50 states plus Washington, D.C. are populated with 2025 rates compiled primarily from the Tax Foundation's annual survey of state individual income tax rates and cross-checked against state revenue departments where available (see our sources page). For progressive states, the head-of-household brackets are approximated with single-filer brackets where a separate official schedule is not published. A few states use personal exemptions rather than a standard deduction; in those cases our model omits the exemption, which can make the estimate slightly high.

Known limitations

• No 401(k), HSA, or other pre-tax contributions.
• No itemized deductions or tax credits (e.g. Child Tax Credit).
• No local/city taxes, state disability insurance (SDI), or unemployment insurance withholding.
• Dependents are collected but not yet applied to credits in this MVP.