How much will a 1GB card hold?

1GB is the same as 1,073,741,824 bytes I'm going to assume that you want to hold either pictures, music or video on your 1GB card. Because of it's limited amount of space the 1GB card is best used for storing pictures or audio files and not video. One hour of standard definition video at 2.2Mbit/s is about 1GB. It will also hold over 17 hours of compressed audio at 128 kbit/s. At the same time it will hold 1000 pictues at 1024×1024 pixel bitmap with 256 colors.