Accuracy and transparency

Conversion methodology

Reviewed: August 16, 2026

Convr is designed around a simple principle: a conversion result should be reproducible from a visible relationship. The calculator, formula, worked example, reference table, and generated page all use the same typed unit data rather than separate hand-entered factors.

Scope of the library

The current library covers length, weight and mass, temperature, volume, and speed. It includes metric and SI units, international customary definitions, separate US and Imperial liquid measures, nautical units, and several scientific scales. Unit names remain explicit whenever a shared word—such as gallon, pint, ounce, mile, or ton—could represent more than one quantity.

Convr converts measurements; it does not estimate uncertainty, calibrate instruments, or decide which reporting precision a regulated workflow requires. Critical engineering, medical, commercial, safety, or legal-metrology results should be checked against the applicable official source and procedure.

Single source of unit definitions

Every unit is stored once in a language-independent data file. Linear categories use a base unit: meter for length, kilogram for mass, liter for volume, and meter per second for speed. Each unit stores its relationship to that base.

result = input × source factor ÷ target factor

Passing through a common base prevents pair-specific factors from drifting apart and ensures that reverse conversions use the reciprocal relationship.

For example, the international inch is exactly 0.0254 meter. A foot is exactly 0.3048 meter. Converting inches to feet compares those two stored relationships. The same values also generate the displayed formula and reference table.

Temperature is handled separately

Temperature scales do not all share the same zero point. A multiplier alone cannot correctly convert Celsius and Fahrenheit readings. Convr represents each scale with both an interval factor and an offset, converts the source reading to a common temperature basis, then transforms that value into the destination scale.

°F = (°C × 9/5) + 32

The factor changes the degree size; the offset aligns the zero points.

Absolute temperature readings and temperature differences are not always interpreted identically. The converter pages calculate readings. Technical work involving an interval or uncertainty should apply the appropriate difference relationship.

Exact definitions and displayed factors

Many modern relationships are exact by definition. Examples include one inch equaling exactly 2.54 centimeters, one pound equaling exactly 0.45359237 kilogram, one nautical mile equaling exactly 1,852 meters, and one liter equaling exactly one cubic decimeter.

A displayed decimal factor may still be rounded for readability when the exact relationship produces a repeating decimal. Calculations use the stored factor values rather than copying the shortened text shown in a headline or formula card.

Precision and rounding policy

Convr retains normal JavaScript double-precision arithmetic throughout a calculation and rounds only the displayed result. Conversion pages allow a user to select 2, 4, 6, or 8 decimal places; the default maximum is 6. Trailing zeros are removed when they add no information, and very large or very small values may use scientific notation.

The number of displayed decimals is not a statement about measurement certainty. A source measured to the nearest centimeter does not become more accurate when its converted result shows eight decimal places. Users should report only the precision justified by the original measurement and their context.

Build-time validation

All public conversion routes are generated from the unit data during the Astro production build. Reviewed editorial files are matched against their category, source unit, destination unit, translation key, and generated formula. A mismatch stops the build instead of publishing contradictory content.

Automated validation also checks the number of conversion pages, editorial coverage, canonical URLs, sitemap membership, hreflang declarations, Open Graph metadata, FAQ, HowTo and breadcrumb structured data, privacy-only behavior, and exclusion of private administration routes from the sitemap.

Reference standards

Primary standards and national metrology guidance take priority over secondary conversion tables. The principal public references used for the framework are:

Corrections

If a unit label, explanation, formula, or result appears incorrect, send the page URL and expected relationship through the Contact page. Reports are checked against the source data and applicable standard. A confirmed correction is applied to the common data or content source so every affected static page is rebuilt consistently.

For how explanatory material is prepared and maintained, read the Editorial policy.