GeraCash / US tax rates / methodology
GUSETR Methodology
Full, reproducible formula for the Gera US Effective Tax Rate (GUSETR). Every input traces to a real, key-free, public-domain US government source. No estimates. No invented numbers.
What is GUSETR?
GUSETR (Gera US Effective Tax Rate) is the percentage of a gross salary that a single filer in a given US state pays in combined federal income tax, FICA, and state income tax for Tax Year 2025. It is a comparison metric — not an individual tax return. It assumes the standard deduction (no itemized deductions) and applies the state’s top marginal rate as an upper-bound proxy.
GUSETR = (federal_income_tax + FICA + state_income_tax) ÷ gross_salary × 100Step 1 — Federal income tax
Source: IRS.gov — Federal income tax rates and brackets (IRS Revenue Procedure 2024-40; US public domain).
Standard deduction (single filer, 2025): $15,000. Taxable income = max(0, gross − $15,000).
| Marginal rate | Taxable income (single, 2025) |
|---|---|
| 10% | $0 – $11,925 |
| 12% | $11,925 – $48,475 |
| 22% | $48,475 – $103,350 |
| 24% | $103,350 – $197,300 |
| 32% | $197,300 – $250,525 |
| 35% | $250,525 – $626,350 |
| 37% | $626,350 – and above |
These are the taxable-income brackets (after standard deduction), not gross income. Marginal rates: only the income in each band is taxed at that rate — not the entire salary.
Step 2 — FICA (Social Security + Medicare)
Source: IRS Topic No. 751 — Social Security and Medicare withholding rates (US public domain).
| Component | Employee rate (2025) | Wage cap |
|---|---|---|
| Social Security | 6.2% | $176,100 wage base |
| Medicare | 1.45% | No cap |
| Additional Medicare Tax (0.9%) on wages > $200,000 is excluded from GUSETR for the salary grid shown. | ||
Only the employee share is included. Employers pay a matching amount separately (not part of GUSETR). The Social Security wage base is adjusted annually; the 2025 figure of $176,100 is from IRS Publication 15 / SSA announcement.
Step 3 — State income tax
Sources: Wikipedia State income tax article (citing Tax Foundation 2025 and individual state DOR pages; US public domain). Each state’s individual DOR page is linked on the state detail page.
GUSETR applies the published top marginal rate to gross salary as an upper-bound proxy:
state_tax = gross_salary × top_marginal_rate- No-income-tax states (9): top_marginal_rate = 0. State tax = $0.
- Flat-rate states (15): the flat rate is the exact effective rate — GUSETR is precise.
- Graduated states (26 + DC): the top rate is an upper bound. Real effective state rates are lower for income below the top bracket threshold. Pages label this explicitly.
Step 4 — GUSETR formula
taxable_income = max(0, gross - 15,000) // 2025 standard deduction (single)
federal_tax = sum(bracket_rate × band_income) // IRS 2025 marginal brackets
fica = min(gross, 176,100) × 0.062 + gross × 0.0145 // SS + Medicare
state_tax = gross × state_top_rate // upper-bound proxy; 0 for no-tax states
GUSETR = round((federal_tax + fica + state_tax) / gross × 100, 1) // %Limitations and disclaimers
- Standard deduction only: itemized deductions (mortgage, charity, SALT) are not modelled. Real federal tax may be lower for those who itemize.
- Filing status: single filer only. Married filing jointly uses different brackets and a higher standard deduction.
- Graduated states use top rate: if your salary is below the top bracket threshold, your actual state rate is lower than GUSETR assumes. See each state’s DOR page for graduated brackets.
- Local income taxes: some cities and counties levy local income tax (e.g. New York City, Philadelphia, Detroit). Local taxes are not included in GUSETR.
- Pre-tax deductions: 401(k), HSA, FSA, and health insurance premiums reduce taxable income and therefore lower real effective rates.
- Not tax advice: GUSETR is a comparison tool. Consult a tax professional for your personal liability.
Data licence
Federal tax brackets and FICA rates are published by the Internal Revenue Service — a US Government work in the public domain under 17 U.S.C. §105 (usa.gov/government-works). State DOR rate tables are published by state government agencies (public domain). The GUSETR computation and presentation are original Gera Systems work (© 2025 Gera Systems Ltd).