<Table> GPT header format <Tr> <Th> Offset </Th> <Th> Length </Th> <Th> Contents </Th> </Tr> <Tr> <Td> 0 (0x00) </Td> <Td> 8 bytes </Td> <Td> Signature ("EFI PART", 45h 46h 49h 20h 50h 41h 52h 54h or 0x5452415020494645ULL on little - endian machines) </Td> </Tr> <Tr> <Td> 8 (0x08) </Td> <Td> 4 bytes </Td> <Td> Revision (for GPT version 1.0 (through at least UEFI version 2.7 (May 2017)), the value is 00h 00h 01h 00h) </Td> </Tr> <Tr> <Td> 12 (0x0C) </Td> <Td> 4 bytes </Td> <Td> Header size in little endian (in bytes, usually 5Ch 00h 00h 00h or 92 bytes) </Td> </Tr> <Tr> <Td> 16 (0x10) </Td> <Td> 4 bytes </Td> <Td> CRC32 / zlib of header (offset + 0 up to header size) in little endian, with this field zeroed during calculation </Td> </Tr> <Tr> <Td> 20 (0x14) </Td> <Td> 4 bytes </Td> <Td> Reserved; must be zero </Td> </Tr> <Tr> <Td> 24 (0x18) </Td> <Td> 8 bytes </Td> <Td> Current LBA (location of this header copy) </Td> </Tr> <Tr> <Td> 32 (0x20) </Td> <Td> 8 bytes </Td> <Td> Backup LBA (location of the other header copy) </Td> </Tr> <Tr> <Td> 40 (0x28) </Td> <Td> 8 bytes </Td> <Td> First usable LBA for partitions (primary partition table last LBA + 1) </Td> </Tr> <Tr> <Td> 48 (0x30) </Td> <Td> 8 bytes </Td> <Td> Last usable LBA (secondary partition table first LBA - 1) </Td> </Tr> <Tr> <Td> 56 (0x38) </Td> <Td> 16 bytes </Td> <Td> Disk GUID (also referred as UUID on UNIXes) </Td> </Tr> <Tr> <Td> 72 (0x48) </Td> <Td> 8 bytes </Td> <Td> Starting LBA of array of partition entries (always 2 in primary copy) </Td> </Tr> <Tr> <Td> 80 (0x50) </Td> <Td> 4 bytes </Td> <Td> Number of partition entries in array </Td> </Tr> <Tr> <Td> 84 (0x54) </Td> <Td> 4 bytes </Td> <Td> Size of a single partition entry (usually 80h or 128) </Td> </Tr> <Tr> <Td> 88 (0x58) </Td> <Td> 4 bytes </Td> <Td> CRC32 / zlib of partition array in little endian </Td> </Tr> <Tr> <Td> 92 (0x5C) </Td> <Td> * </Td> <Td> Reserved; must be zeroes for the rest of the block (420 bytes for a sector size of 512 bytes; but can be more with larger sector sizes) </Td> </Tr> </Table> <Tr> <Th> Offset </Th> <Th> Length </Th> <Th> Contents </Th> </Tr> <Tr> <Td> 0 (0x00) </Td> <Td> 8 bytes </Td> <Td> Signature ("EFI PART", 45h 46h 49h 20h 50h 41h 52h 54h or 0x5452415020494645ULL on little - endian machines) </Td> </Tr> <Tr> <Td> 8 (0x08) </Td> <Td> 4 bytes </Td> <Td> Revision (for GPT version 1.0 (through at least UEFI version 2.7 (May 2017)), the value is 00h 00h 01h 00h) </Td> </Tr>

The guid partition table method for partitioning a drive allows up to 128 partitions