What is the octane rating of shell diesel fuel?

It should be listed on the pump. Generally speaking, diesel fuel ignition quality is not measured in octanes, as these are a unit for gasoline. Diesel fuel is measured in cetane not octane.

• Regular diesel--48
• Premium diesel--55
• Biodiesel (B100)--55
• Biodiesel blend (B20)--50
• Synthetic diesel--55

A label should be affixed to the pump that states both the fuel type and cetane number. It's important to find a station that dispenses fuel of the cetane number recommended by the vehicle manufacturer.