For ANY aircraft fitted with Flight Path Angle / Flight Path Vector indication (or "The bird" on your A320), multiply the Climb (or descent) gradient in % by 0.6 to convert to degrees. The FPA/FPV indicates (or is selectable) in degrees. For your 7% gradient, 7 X 0.6 = 4.2 degrees FPA/FPV. A piece of cake and dead accurate.
Regards,
Old Smokey