Trust and methodology
Learn how UnitConversion.free handles conversion logic, supported units, rounding guidance, and trust questions before you rely on a result.
Use this page for trust intent: review how the site approaches conversion logic, supported-unit coverage, rounding guidance, and common questions before relying on a result.
UnitConversion.free uses a typed unit catalog and conversion engine for every result rather than a static lookup table. Conversions are computed from the defined base factors in the catalog, so accuracy is bounded by the precision of those constants and by JavaScript double-precision arithmetic. For safety-critical, legal, or regulated work, verify the final value against your governing standard.
17 dimensions are covered: length, mass, temperature, volume, speed, area, time, pressure, energy, power, frequency, angle, digital storage, data rate, force, fuel economy, and density. Each dimension has its own route with the most common unit pairs surfaced first, plus dedicated pair-specific calculator pages for popular conversions like meters to feet, Celsius to Fahrenheit, and MPG to L/100km.
No. All conversions run entirely in your browser. The site stores only your theme preference in local storage so the light, dark, or system mode choice persists across reloads. No conversion inputs, results, or usage history are sent to a server.
Cite the source unit, the target unit, the numeric result, and the page you used (for example: "Meters to Feet Converter at https://unitconversion.free/meters-to-feet"). For academic or engineering work, cross-reference the result with an authoritative standard such as NIST SP 811 (US) or BIPM's SI brochure (international) so the primary reference is the standard, not the calculator.
Yes. The header includes explicit Light, Dark, and System choices, and your selection persists across reloads.
Yes. The desktop side rail collapses into a horizontal category strip, and the main cards scale down for smaller screens without changing the route structure.