Free Calculator
Image File Size Estimator
Estimate image file size based on dimensions, format, and quality. Useful for planning storage, bandwidth, and web performance.
Estimated File Size
540 KB
Medium JPEG compression
Format Comparison
| Format | Best For | Compression | Transparency | Typical Size (1920×1080) |
|---|---|---|---|---|
| JPEG (High) | Photos, web images | Lossy (90% quality) | No | 800-1200 KB |
| JPEG (Medium) | Web optimization | Lossy (75% quality) | No | 400-700 KB |
| JPEG (Low) | Thumbnails, previews | Lossy (60% quality) | No | 200-400 KB |
| PNG-24 | Graphics with transparency | Lossless | Yes (full alpha) | 2-4 MB |
| PNG-8 | Simple graphics, icons | Lossless (256 colors) | Yes (1-bit) | 300-800 KB |
| WebP (Lossy) | Modern web, photos | Lossy (better than JPEG) | Yes | 300-500 KB |
| WebP (Lossless) | Graphics needing quality | Lossless | Yes | 1-2 MB |
| GIF | Animations, simple graphics | Lossless (256 colors) | Yes (1-bit) | 500-1500 KB |
How This Calculator Works
This calculator estimates file size using typical compression ratios for each format:
- JPEG: Bytes per pixel varies by quality (0.2-0.6 bpp typical)
- PNG: Lossless, size depends on image complexity (1-4 bytes per pixel)
- WebP: 25-35% smaller than JPEG for same quality
- GIF: Limited to 256 colors, best for simple graphics
When to Use Each Format
- JPEG: Photos, complex images, no transparency needed. Best for web.
- PNG: Logos, graphics, screenshots with transparency. Lossless quality.
- WebP: Modern replacement for JPEG/PNG. Smaller sizes, better quality. Use when browser support allows.
- GIF: Animations only. Use video for longer animations.
Optimization Tips
- Use JPEG quality 75-85% for web — indistinguishable from 100% but much smaller
- WebP can save 30% file size vs JPEG with no visible quality loss
- For photos, JPEG or WebP lossy. For graphics, PNG or WebP lossless
- Compress images before upload using tools like TinyPNG or ImageOptim
- Serve responsive images — don't send 4K images to mobile users