Compression
Does zipping photos and videos save space?
≈ 0% saved
for JPEG photos and MP4 videos: they are already compressed. Zip helps text-like files a lot.
Hardly at all. JPEG, HEIF, MP3 and MP4 are already compressed, and compressing compressed data finds almost nothing left to remove. Text, spreadsheets and logs are another story.
The arithmetic
- A compressor removes repetition and predictability
- JPEG, HEIF, MP3 and MP4 already removed it when the file was made
- What is left looks random to zip, so the archive is about the same size, sometimes a little bigger
| File type | Typical ratio |
|---|---|
| Plain text, CSV, logs | 3:1 – 10:1 |
| HTML, JSON, source code | 3:1 – 8:1 |
| Office documents (.docx, .xlsx) | ≈ 1:1 (already zipped inside) |
| JPEG / HEIF photos | ≈ 1:1 (1–3 % saving) |
| MP3 / AAC music | ≈ 1:1 |
| MP4 / MOV video | ≈ 1:1 |
| BMP / uncompressed TIFF | 2:1 – 4:1 |
| WAV audio | 1.1:1 – 1.3:1 with zip; ~2:1 with FLAC |