About Calcflux
21 unit categories, thousands of conversion pages, and 38 calculators covering finance, health, math, engineering, and more. Available in English, German, Spanish, French, and Portuguese. Every page loads in under two seconds.
How we get the numbers right
Every conversion factor is sourced from NIST SP 330 and the ISO 80000 series. For example, 1 inch is defined as exactly 25.4 millimeters, and 1 pound (avoirdupois) equals exactly 0.45359237 kilograms. Temperature conversions between Celsius, Fahrenheit, Kelvin, and Rankine use the exact thermodynamic formulas, not rounded approximations. All math runs to 15+ significant digits of precision, the same standard used by scientific calculators and spreadsheets. The conversion formula is displayed alongside every result so you can verify the math independently.
Testing and verification
An automated test suite runs thousands of checks on every code change, covering known reference values, boundary conditions, and edge cases — including the temperature anchors 0 °C = 32 °F, 100 °C = 212 °F, and −40 °C = −40 °F.
Privacy and contact
No account needed. No tracking cookies set by Calcflux itself. Your conversion inputs and calculation results never leave your browser. See our privacy page for full details on analytics and crash reporting.
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