Work out octane number blending instantly with clear inputs, formula shown and shareable results.
Octane numbers blend approximately linearly by volume, so the blend rating is the volume-weighted average of the components. Sixty litres of 91 with forty litres of 98 gives 93.8. Real refinery blending uses blending octane numbers that differ slightly from the neat values because components interact, but volumetric averaging is the standard first estimate.
Volumetric blend
octane = (V1 x O1 + V2 x O2) / (V1 + V2)
Volume share
share = V1 / (V1 + V2)
Close but not exactly. Aromatics and ethanol show non-linear blending, so refiners use empirically corrected blending values for precise work.
No. Octane measures resistance to knock, not energy content. High-octane petrol often carries slightly less energy per litre.