micro SD cards -- actual size vs. claims

[tllim]

Try 32*(1000*1000*1000)/(1024*1024*1024) = 32*10^9/2^30 = 29.8GB. Then take off partition table and file system overhead...

Over pass few months try out varies microSD card, I also surprise that capacity stated in all microSD card can be different from one manufacturer to the others. Using 8GB miocroSD card as example, the brand "S" one actually has 8GB, the brand "T" one only has 7.2GB.
I always need to collect the smallest capacity of microSD card in each 8GB, 16GB, 32GB, and 64GB category, so that I can create the DD image that can fit for all.