Science & Engineering

Compression Ratio Calculator (File Size)

Enter the original and compressed file sizes and you get the compression ratio in X:1 form plus the percentage of space saved. It works for ZIP, JPEG, MP3, H.264, or any format.

How to use
  1. Enter the original file size.
  2. Enter the compressed file size.
  3. Check the percentage of space saved.
Try
Compression ratio
5 : 1

100 MB → 20 MB

Space saved
80%
Size reduction
80 MB
Bits per byte
1.6 bits
For study and estimation. Verify against authoritative data before relying on a result.
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Common questions

What does a 4:1 compression ratio mean?

It means the original file is four times the size of the compressed one, which is a 75% space saving.

How do I find the percentage saved?

Subtract the compressed size from the original, divide by the original, and multiply by 100.

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