Calculate compression metrics for your files to understand storage efficiency
2.50:1
Original size is 2.50 times larger than compressed size
60.00%
Percentage of storage space saved through compression
0.40
Fraction of original size (lower is better)
3.20
Average bits needed to represent 8 bits of original data
This Compression Ratio Calculator helps you understand how effectively your files are being compressed by comparing original and compressed file sizes. Whether you're optimizing storage space, improving file transfer speeds, or evaluating compression algorithms, this tool provides key metrics to measure compression effectiveness.
Compression ratio measures the relative reduction in file size achieved through data compression. It's typically expressed as a ratio of the original size to the compressed size (e.g., 5:1). A higher compression ratio indicates more effective compression, meaning the file has been reduced to a smaller fraction of its original size.
For example, if a 100MB file is compressed to 20MB, the compression ratio would be 5:1, indicating the original file was five times larger than the compressed version.
If you want to learn more about these metrics, switch to the "Information" tab for detailed explanations.
| Metric | Formula | Interpretation | Ideal Value |
|---|---|---|---|
| Compression Ratio | Original Size ÷ Compressed Size | How many times larger the original file is compared to the compressed version | Higher is better (e.g., 10:1) |
| Space Savings | ((Original - Compressed) ÷ Original) × 100% | Percentage of storage space saved through compression | Higher is better (closer to 100%) |
| Compression Factor | Compressed Size ÷ Original Size | Fraction of original size remaining after compression | Lower is better (closer to 0) |
| Bits per Bit | 8 × Compression Factor | Average bits needed to represent 8 bits (1 byte) of original data | Lower is better (less than 8) |
| File Type | Typical Compression Ratio | Space Savings | Notes |
|---|---|---|---|
| Plain Text (TXT) | 1.5:1 to 3:1 | 33% to 67% | Higher with repetitive content |
| Documents (DOC, PDF) | 2:1 to 4:1 | 50% to 75% | Varies with embedded images |
| Spreadsheets (XLS, CSV) | 3:1 to 6:1 | 67% to 83% | Higher with repetitive data patterns |
| Compressed Images (JPG, PNG) | 1.1:1 to 1.5:1 | 9% to 33% | Already compressed, limited additional gains |
| Raw Images (BMP, TIFF) | 3:1 to 10:1 | 67% to 90% | High compression potential |
| Audio (uncompressed WAV) | 3:1 to 10:1 | 67% to 90% | Lossless vs. lossy compression |
| Video (uncompressed) | 10:1 to 100:1 | 90% to 99% | Typically uses lossy compression |
| Program Executables | 2:1 to 4:1 | 50% to 75% | Many are pre-compressed during build |
There are two main approaches to data compression, each with different characteristics and use cases:
| Feature | Lossless Compression | Lossy Compression |
|---|---|---|
| Data Integrity | Preserves all original data | Discards some data permanently |
| Reconstruction | Perfect reconstruction of original | Approximation of original |
| Compression Ratio | Typically 2:1 to 5:1 | Can exceed 20:1 or higher |
| Common Formats | ZIP, GZIP, PNG, FLAC | JPEG, MP3, MP4, WebP |
| Best For | Text, databases, program files | Images, audio, video |
Several factors influence how effectively data can be compressed:
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