Exactly double the burn rate of a leisure ride, for the same bike and the same route.
Riding at a brisk, purposeful pace asks your legs to push against more resistance with every pedal stroke, and keeps your heart rate elevated continuously rather than coasting between efforts. That sustained higher output is what separates moderate cycling from a leisure ride, even on identical terrain.
At 8.0 MET, moderate cycling matches tennis and HIIT for calorie burn, and exactly doubles the rate of leisure cycling at 4.0 MET.