A GB of data generally equals to about 1000 megabytes (MB) of download data. So, a 1GB download would use about 1000MB, or 1024MB to be precise. This amount is equal to about 8,000 megabits (Mb) of data transfer.
To put it simply; a 1GB download would require about 8,000 megabits (or 8 megabytes) of data usage in order to be complete. This is equivalent to approximately 1.5 hours of standard streaming video or 50 hours of music. Of course, this amount will vary depending on the type of data you're downloading. For example, downloading a high definition movie could use significantly more than 1GB of data.