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Rule Calculator

Tools

The calculators that could not be written as a formula over a few numbers. Each takes something the catalogue's specs cannot express — a list, a pay period, an IP address, two time zones — and each shows the working the same way the catalogue does.

Numbers and lists

Anything whose input is more than one figure — a column pasted from a spreadsheet, a set of grades, a radicand.

Money

Each one carries the date of the data behind it, because a rate or an index without a date is a claim about right now.

Tax

Federal withholding from Publication 15-T, and the state line that decides how different two identical salaries feel.

Time and place

Clocks, zones and the weeks of the year when the usual difference between two of them is wrong.

Networks

The two prefixes every other subnet calculator gets wrong are the ones this was built for.

Body

Estimates from published formulas, reported as the ranges those formulas actually produce.

Chance

Drawn from the browser’s cryptographic generator without modulo bias, and printed beside the odds of what you got.

Also here

Calculators for Supply YardsAP Score DistributionsSAT Scores by StateACT Composite and Scores by StateStem and Leaf Plot GeneratorP-Value CalculatorZ TableT TableGCF and LCM of Any PairFinancial CalculatorBig Number CalculatorDecimals as FractionsHow Old Am I, by Birth YearRoman Numeral ConverterRoman Numeral Date ConverterNumber to Words ConverterTruth Table GeneratorCubic Equation SolverIncome Tax CalculatorIRR CalculatorBond CalculatorRGB to Hex ConverterASCII TableBinary TranslatorBinary to Decimal ConverterkVA to kW CalculatorWire Size CalculatorMarriage Tax Calculator

Every one of these is also an endpoint

31 of them answer over HTTP and through the MCP server as well as on the page, so a model or a script can call them and get back the answer, the working and the source it came from. The API page has the shapes.