Transparent calculators, source-backed rules, reproducible tests

Who maintains PayCalc

PayCalc.org is an independent financial-calculator project maintained by its Editorial & Engineering team. The site is not operated by the IRS, a state revenue agency, a mortgage lender, a brokerage, or an accounting firm. PayCalc does not claim review by a CPA, attorney, mortgage professional, or investment adviser unless a page explicitly says so.

Why PayCalc exists

Many calculators produce a number without exposing the rule source, edge cases, or assumptions behind it. PayCalc's goal is to make common financial estimates easier to inspect. The paycheck calculator is the clearest example: the public tool is backed by a jurisdiction-by-jurisdiction 2026 rule dataset, source URLs, verification dates, automated tests, and live browser regression cases.

How calculators and content are produced

Engineering begins with the model or official rule, not with a target keyword. Federal and state payroll rules are implemented from government publications or agency guidance and stored as structured data. Mortgage and investment tools use documented mathematical models. Automated tests exercise the engines, and Playwright tests verify representative results in the browser and on the deployed site.

Automation and AI tools may assist with research organization, drafting, code generation, refactoring, and test development. We do not treat generated text as an authority. Where a rule is source-dependent, the official source and verified implementation take priority. The site publishes source provenance and representative regression outputs so visitors can inspect important claims.

What makes the site different from a generic calculator script

• A 2026 payroll rule set for federal, every U.S. state, and the District of Columbia, with primary-source metadata.
• State-specific behavior such as California SDI, Washington Paid Leave and WA Cares, Indiana county withholding inputs, and jurisdiction-specific allowance systems.
• Published browser-regression scenarios that users can reproduce.
• Scheduled source monitors for selected jurisdictions and a daily live browser regression.
• Public methodology, editorial standards, limitations, and a material update history.

How we handle accuracy

Accuracy is treated as an engineering process rather than a badge. A passing automated test proves that software matches an expected result; it does not prove the expected rule is legally correct forever. PayCalc pairs tests with official-source provenance and tax-year metadata.

See the Accuracy & Testing Center and 2026 Payroll Tax Source Directory.

What PayCalc does not do

PayCalc does not prepare tax returns, run payroll, underwrite mortgages, provide individualized investment recommendations, or store a professional financial profile. Results are estimates for education and planning. Real outcomes can depend on employer configuration, forms, local law, loan contracts, fees, market returns, and facts not entered into a general-purpose calculator.

Corrections and maintenance

When a source, formula, label, or test is wrong, the objective is to correct implementation and explanation together. Material changes are recorded in the Update History. We do not change dates merely to create an appearance of freshness.