The compression ratio reflects the ratio of file size that exists between a compressed signal and an uncompressed signal. The compression ratio, also known as the compression factor or K-factor, is expressed as the ratio of the compressed file size to the original file size.
For example, a compression ratio of 1:100 states that the file size after compression is one-hundredth of the previous file size. Instead of specifying the ratio, the compression ratio can also be specified as a percentage, for example 94%. This means that the file size of the compressed file has been reduced by 94% compared to the original file.
The compression rate depends largely on the type of compression. A lossless compression will always have a lower compression rate than a lossy compression. Furthermore, the compression rate depends on the type of media: Data has lower compression than audio or video, for example.
The range of compression rates is between 1:1,. and 1:1,000 and higher as for example in the compression of video sequences according to H.261.