About

Build: v1.1.3+20260829190447

A public methane number calculator for gas mixtures, built around ISO 17507-1:2025.

The app is intended for engineers, laboratories, and gas professionals who need a practical way to evaluate calculated methane number for natural gas, biomethane, biogas, and hydrogen-containing gas mixtures.

Methane number is used to describe the knock resistance of gaseous fuels for reciprocating internal combustion engines. The calculated methane number method in ISO 17507-1:2025 belongs to the established methane number tradition behind terms such as Methanzahl, the MWM Method, and earlier AVL/FVV work on methane-hydrogen reference mixtures and ternary gas mixture data. Related methane number references include EN 16726, ASTM D8221, and ISO 23306.

The calculation core is designed to closely follow the ISO 17507-1:2025 calculated methane number method for the supported components, input basis conversions, normalization, method limits, ternary systems, and inert correction used by the application. It is not presented as an official or certified reference implementation.

The calculator accepts volume, mole, or mass fractions and converts the input to the volume-fraction basis used by the ISO 17507-1:2025 calculation method.

The Annex A.10 comparison page shows additional validation data for users who know the standard and want to inspect reference examples, spread values, and selected or eliminated ternary systems.