USB Storage Capacity

The capacity of USB flash drives varies, covering multiple specifications from smaller to larger capacities to meet the storage needs of different users. Currently, the common capacities of USB flash drives include 16GB, 32GB, 64GB, 128GB, 256GB, 512GB, and even 1TB, 2TB, etc.

Capacity

Small Capacity

256MB，512MB
1GB，2GB，4GB，8GB，16GB

Middle Capacity

32GB (most popular) 64GB (most popular) 128GB

Large Capacity

256GB
1TB
2TB

Difference between nominal capacity and actual capacity:
Since the nominal capacity of storage devices is usually calculated according to 1GB=1000MB, 1MB=1000KB, 1KB=1000B, while the computer system recognizes the storage capacity according to 1GB=1024MB, 1MB=1024KB, 1KB=1024B, the actual usable capacity of USB flash drives is slightly smaller than the nominal capacity. Therefore, the actual usable capacity of USB flash disk will be slightly smaller than the nominal capacity. Generally speaking, the actual usable capacity of a USB flash drive with a nominal capacity of 16GB is around 14.5GB to 15GB.
System Occupancy and Hidden Partition:
Some USB flash drives have built-in system files or hidden partitions for storing device drivers, encryption software, etc., which will further reduce the actual usable capacity. For example, some encrypted USB flash drives may take up hundreds of MB or even more than 1GB of space for their encryption software.

Nominal capacity	The approximate value of the actual available capacity (calculated according to 1GB = 1000MB, 1MB = 1000KB, 1KB = 1000B and then converted into the capacity recognized by the computer)
1GB	1000MB / 1024 ≈ 0.9766GB
2GB	2000MB / 1024 ≈ 1.9531GB
4GB	4000MB / 1024 ≈ 3.9063GB
8GB	8000MB / 1024 ≈ 7.8125GB
16GB	16000MB / 1024 / 1024 / 1024 ≈ 14.90GB125
32GB	32000MB / 1024 / 1024 / 1024 ≈ 29.80GB17
64GB	64000MB / 1024 / 1024 / 1024 ≈ 59.60GB17
128GB	128000MB / 1024 / 1024 / 1024 ≈ 119.21GB17
256GB	256000MB / 1024 / 1024 / 1024 ≈ 238.42GB
512GB	512000MB / 1024 / 1024 / 1024 ≈ 476.84GB
1TB	1000000MB / 1024 / 1024 / 1024 ≈ 0.9095TB
2TB	2000000MB / 1024 / 1024 / 1024 ≈ 1.819TB