| TABLE 1: FAT Cluster/Allocation Unit Size by Volume Size |
| Volume-Size Range |
Default Cluster (Allocation Unit) Size |
| 0 to 15MB* |
4KB |
| 16MB to 31MB | 0.5KB |
| 32MB to 63MB |
1KB |
| 64MB to 127MB |
2KB |
| 128MB to 255MB | 4KB |
| 256MB to 511MB | 8KB |
| 512MB to 1023MB | 16KB |
| 1024MB to 2047MB | 32KB |
| 2048MB to 4095MB | 64KB |
| 4096MB to 8191MB | 128KB** |
| 8192MB or larger | 256KB** |
| *FAT volumes smaller than 16MB use a 12-bit FAT (FAT12) file system. |
| **To support 4GB or larger FAT partitions that use 128KB or 256KB clusters, the drives must use sectors larger than 512 bytes. |