What Numera Is
Numera is a collection of 20 free calculators and converters in two families: math and statistics (fractions, percentages, base conversion, trigonometry, logarithms, boolean algebra, standard deviation, linear regression, primes, factorials, quadratic equations, geometry) and unit conversion (length, weight, volume, area, temperature, speed, CSS typography units, and medical weight units). Every tool runs entirely in your browser — the numbers and datasets you enter are never sent to a server.
Why We Built It
Calculator sites tend to hide one working tool under layers of advertising, or round their conversion factors to three decimal places. We built the opposite: standard formulas applied at full precision, every assumption stated on the page, and an automated test suite verifying the core logic against known reference values — the classic standard deviation dataset, the exact mile-to-meter definition, known prime factorizations.
How the Tools Work
Unit conversions use the internationally defined exact factors — 1 mile is precisely 1,609.344 meters by international agreement, not a rounded approximation. Statistics calculators apply the standard population and sample formulas. The boolean evaluator uses a proper recursive-descent parser with correct operator precedence. Big-integer arithmetic keeps factorials exact where ordinary calculators overflow.
Our Standards
Core logic passes automated tests before publication, pages state their limits (integer ranges, line caps, precision boundaries), and estimates are labeled as estimates. Corrections reported through the contact page are typically deployed within days.
The Short Version
Free tools, local computation, exact factors, tested formulas, stated limits. That's the whole model.