File Compression Ratio Calculator
Calculate a file's compression ratio and percentage of space saved from its original and compressed sizes.
MB
MB
Results
Compression Ratio
3.2:1
Space Saved
69.0%
How to Use the File Compression Ratio Calculator
Enter a file's original size and its compressed size (in the same unit, such as MB) to see how effectively it was compressed. The compression ratio expresses how many times smaller the compressed file is compared to the original, while space saved shows that same reduction as a percentage.
Compression Ratio = Original Size / Compressed Size
Space Saved % = (1 − Compressed Size / Original Size) × 100
Space Saved % = (1 − Compressed Size / Original Size) × 100
Example
A 100 MB file compressed down to 31 MB has a compression ratio of 100 / 31 ≈ 3.2:1, meaning the original is about 3.2 times larger than the compressed version, and it saved (1 − 31/100) × 100 = 69% of space.
Common Use Cases
- Comparing how well different compression formats (ZIP, 7z, video codecs) shrink the same file.
- Evaluating image or video compression settings before publishing or archiving content.
- Estimating storage or bandwidth savings from compressing a batch of files.
FAQs
- Is this the same as the Compression Ratio Calculator already on this site? No — that calculator computes an engine's compression ratio from cylinder bore, stroke, and combustion chamber volume, an entirely different automotive/mechanical concept that just happens to share a similar name. This calculator is about data and file compression — zip archives, images, video, and similar.
- What's a good compression ratio? It depends heavily on the file type and format — text and uncompressed formats often compress 3:1 to 10:1 or more, while already-compressed formats like JPEG images or MP4 videos typically see much smaller further gains since most of the redundancy is already removed.
- Does a higher compression ratio always mean better compression? Not necessarily on its own — very high ratios on lossy formats (like images or video) can come at the cost of visible quality loss, so it's worth weighing compression ratio against acceptable quality for your use case.