MBR vs GPT
Also known as: master boot record, GUID partition table, partition scheme, MBR or GPT
MBR (Master Boot Record) and GPT (GUID Partition Table) are the two schemes that define how a drive is partitioned and booted. MBR is older and limited to 2 TB and four primary partitions; GPT is the modern standard, supporting far larger drives and many more partitions.
- Two partition schemes: older MBR and modern GPT
- MBR caps drives at 2 TB and four primary partitions
- GPT supports large drives and pairs with UEFI
What a partition scheme does
Before a drive can hold partitions, it needs a partition table that records where each partition begins and ends and how the system boots. MBR dates to early PCs and uses 32-bit addressing, which caps a drive at 2 TB and allows only four primary partitions.
GPT replaces it with a modern layout: it handles much larger drives, supports many partitions, and keeps a backup copy of the partition table for resilience. It pairs with UEFI firmware, the successor to the old BIOS.
Which one you have
New computers and large drives use GPT by default; you will only meet MBR on older systems, small USB sticks, or drives kept compatible with legacy hardware. On Windows you can check a disk’s scheme in Disk Management, and on macOS in Disk Utility.
Converting between the two usually requires reformatting or specialized tools, so it is decided when a drive is first partitioned. For any modern drive, GPT is the right choice.