16GB=approximately 14GB-15GB 32GB=approximately 28GB-30GB 64GB=approximately 58GB-60GB 128GB=approximately 115GB-120GB 256GB:approximately 230GB-238GB This is calculation difference between manufacturer(1GB=1000MB) and our PC(1GB=1024MB), please Google Memory card capacity to get more information Based on internal testing; performance may be lower depending upon host device.
The SD card association defines card speeds using two terms: Speed Class and UHS Speed Class. Speed class is the original rating used and the number defines the card speed; 4 for 4 MB/s, 6 for 6 MB/s. 10 for 10 MB/s etc. UHS (Ultra High Speed) uses minimum write speeds to differentiate the cards; UHS-I Speed Class 1 has a minimum write speed of 10 MB/s while UHS-I Speed Class 3 has a minimum write speed of 30 MB/s. Speed based on internal testing: Performance may be lower depending on host device, interface, usage conditions and other factors. 1 MB = 1,000,000 bytes Please don’t use a cheap card reader to test Micro SD card. The speed will be affected by low quality card reader.