Amputation depends upon several factors, therefore there is no short answer to this question. Gangrene of the great toe is not dangerous, therefore one can often wait for the patient to be stable. However, diabetic gangrene may extend to affect the foot, therefore prolonged delay is also not a good idea. The appearance of the gangrene may be dry or wet . Wet gangrene needs earlier surgery.
In general, most patients would be operated within 1-2 weeks.