Calculator Methodology & Data Sources
Transparency is our core principle. Here is exactly how we source our data, calculate our estimations, and protect your privacy.
🔒 100% Client-Side Privacy
Every calculator on Ultimate Info Guide runs entirely in your local browser (client-side). We do not capture, store, or transmit your financial inputs to any database or server. When you close the tab, your data disappears. Your privacy is mathematically guaranteed.
📊 How We Build Our Calculators
Our development and research teams do not guess or approximate financial formulas. We build our tools by directly referencing the public documentation, tax tables, and API pricing limits provided by federal institutions, state governments, and corporate platforms.
Because tax codes and platform fees change frequently, we conduct quarterly reviews of our high-traffic calculators to ensure multipliers and brackets remain accurate.
🏛️ Tax & Payroll Data Sources
For our federal tax, payroll, and 1099 contractor estimators, we utilize a progressive bracket architecture that directly mirrors the formulas used by certified accountants. Our primary data sources include:
Internal Revenue Service (IRS)
We source all progressive tax brackets, standard deduction amounts, and FICA wage limits directly from official IRS publications, specifically:
- IRS Form 1040-ES (Estimated Tax)
- IRS Publication 15 (Circular E, Employer’s Tax Guide)
- Schedule SE (Self-Employment Tax)
Department of Labor (FLSA)
For our hourly, overtime, and salary conversion tools, we reference the Fair Labor Standards Act (FLSA) guidelines regarding 40-hour workweeks and mandatory time-and-a-half multipliers.
State Labor Departments
For localized tools (such as our California Double Time Pay Calculator), we explicitly integrate state-specific labor codes, such as the California DIR 12-hour shift and 7th consecutive workday rules.
💳 Business & Platform Fee Calculators
For tools designed for independent creators, e-commerce sellers, and freelancers, we scrape and verify the exact pricing tiers published by the respective corporate platforms. This includes:
- Stripe & PayPal: We utilize their base domestic transaction rates (e.g., 2.9% + $0.30) while factoring in flat-rate percentage caps.
- Etsy & Amazon FBA: We incorporate current listing fees, mandatory transaction cuts, and offsite ad fee logic published in their respective seller central portals.
⚠️ Accuracy & Margins of Error
While we meticulously maintain our calculation logic, our tools provide estimations, not finalized accounting. True tax liability and final net pay involve highly complex, individualized factors that a web browser cannot fully capture, including:
- Local municipality and city-specific tax levies.
- Highly specific, non-standard itemized deductions.
- Employer-specific healthcare premium deductions and union dues.
- Mid-year federal or state tax code revisions.