Android erasure times are the following:
- 32GB device, 1 pass overwriting: 10-15 mins
- 128GB device, 1 pass overwriting: 25-45 mins
Modern high-end devices are typically erased much faster then older and lower-end devices. If several overwriting passes are used (for example NSA 130-1 with 3 passes), the erasure time will increase accordingly.
iOS erasure takes 3-15 minutes (if no firmware downloading is needed). If overwriting is used in addition to iOS firmware update, the erasure time will increase.