Conversion factors

Every unit is defined relative to a reference unit for its category. Conversions are performed by multiplying the input value by the ratio between the source unit's factor and the target unit's factor. This keeps the logic consistent across length, mass, volume, area, speed, and other categories.

Scale and offset conversions

Some units, such as temperatures, require both a scale factor and an offset. For these, we apply the offset after scaling to preserve the correct physical meaning rather than treating them as simple ratios.

Exact vs approximate constants

Constants that are fixed by international agreement are treated as exact. Measured or conventional constants, such as regional definitions or practical cooking measures, are treated as approximate and labeled accordingly.

Rounding and significant figures

Calculations are carried out with full floating-point precision internally. The displayed value is rounded to a sensible number of decimal places based on the category and the magnitude of the result. Users can override decimal places when the interface allows it.

Regional differences

Regional units such as gallons, cups, miles, and stones can vary by country. We label each variant with its regional standard so you can choose the version that matches your source material.

Time-zone logic

Time-zone comparisons use the IANA Time Zone Database. Calculations account for standard and daylight saving offsets as known for the selected city and date.

Running formulas

Running tools convert between pace, distance, and duration using standard relationships. Race projections use validated estimation models and are labeled with their intended use case.

Pizza area calculations

Pizza comparisons calculate the area of each size from its diameter, then compare price per unit area. Optional crust adjustment reduces the effective area to account for a non-topping border.

Testing and review

Conversion logic is covered by automated tests against known reference values. Pages and interactive components are manually reviewed for accuracy and usability before release.