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.