U.S. Sources & Update Methodology

Solveberry’s U.S. calculators are built around official rules, rates and effective dates. This page explains which sources are preferred, how year-specific values are handled, and what the calculators deliberately do not claim to replace.

Primary-source hierarchy

When a U.S. calculation depends on a government rule, Solveberry prefers the agency responsible for that rule. Current examples include the Internal Revenue Service for federal tax and retirement limits, Social Security Administration for Social Security wage-base values, U.S. Department of Labor for federal and state wage references, Office of Personnel Management for federal holidays, and General Services Administration for per-diem rates. State-specific rules should use the relevant state agency or official statute source where practicable.

Effective dates matter

A rate is not treated as timeless. Tax-year limits, fiscal-year per-diem rates, mid-year mileage changes and state wage changes are scoped to their effective dates. If one calendar year contains more than one valid rate, the calculator should ask for or infer the applicable period instead of applying one value to the whole year.

Versioning convention

Year-specific tools identify the year in the page title and methodology. A page labeled 2026 is designed for 2026 rules unless it explicitly supports another period. When a new tax year is released, Solveberry should update the calculation only after the official source is available and the new values have been regression-tested.

Calculation validation

Each rule-based tool is checked against representative examples before release. The visible formula or rule description should be sufficient to reproduce the result independently. Where a tool has material exclusions, those exclusions are stated on the page rather than hidden behind a single output.

Current U.S. source map

Scope and exclusions

Solveberry calculators are focused estimators, not full tax-return, payroll, legal or benefits systems. A federal tax calculator may exclude state tax, credits or special categories; an RMD calculator may exclude inherited accounts or special spouse tables; a wage calculator may not capture every local ordinance. The page should state those boundaries clearly.

No government affiliation

Solveberry is an independent web utility publisher. It is not affiliated with or endorsed by the IRS, SSA, DOL, OPM, GSA or any state government. Links to government sources are provided so users can verify the rule directly.

Corrections and maintenance

If an official source changes, a calculation is found to be wrong, or a material limitation is missing, the affected page should be corrected and its review date updated. Changes that alter results are treated as calculation releases, not silent SEO refreshes.

Last reviewed

2026-09-17. This methodology page should itself be reviewed when the U.S. calculator architecture or source policy changes.