In determining the amount of the penalty, the Upper Tribunal must have regard to the amount of unpaid tax, or amount unpaid in respect of a tax credit.
Wrth ddyfarnu maint y gosb, mae’n rhaid i’r Tribiwnlys Uchaf ystyried swm y dreth sydd heb ei dalu, neu faint sydd heb ei dalu mewn perthynas â chredyd treth.