Estimate the file size of an image from its dimensions, DPI, color depth, and format. Also convert between pixels, inches, and centimeters.
Convert between pixels, inches, and centimeters using a DPI value.
Fill in any one field (pixels, inches, or cm) and the others will be calculated automatically.
Find the maximum print size for an image at a given DPI, or the required resolution for a target print size.
| Format | Estimated Size | Best For |
|---|
| DPI | Use Case |
|---|---|
| 72 dpi | Screen / web display |
| 96 dpi | Windows screen standard |
| 150 dpi | Draft / low-quality print |
| 300 dpi | Professional print standard |
| 600 dpi | High-resolution / large format print |
| 1200 dpi | Fine art / archival scanning |
Image resolution refers to the number of pixels (picture elements) in an image, typically expressed as width × height in pixels. A 1920×1080 image contains 2,073,600 pixels — about 2 megapixels. Resolution determines the maximum size at which an image can be displayed or printed without appearing blurry or pixelated.
DPI stands for Dots Per Inch — the number of printed dots that fit within one inch. Higher DPI means more detail in print. For digital displays, PPI (Pixels Per Inch) is used instead, though the terms are often used interchangeably. The standard for professional print is 300 DPI. For web and screen, 72–96 DPI is sufficient since monitors have their own pixel density.
The uncompressed file size of an image is: Width × Height × Bits per pixel ÷ 8 (to convert bits to bytes). A 1920×1080 RGB image has 1920 × 1080 × 24 bits = 49,766,400 bits = 6,220,800 bytes ≈ 5.93 MB uncompressed. Formats like JPEG, PNG, and WebP apply compression to reduce this significantly.
| Format | Compression | Transparency | Best For |
|---|---|---|---|
| JPEG | Lossy | No | Photos, web images |
| PNG | Lossless | Yes | Graphics, logos, screenshots |
| WebP | Lossy/Lossless | Yes | Web images (modern browsers) |
| HEIC | Lossy | No | iPhone photos, small files |
| TIFF | Lossless | Yes | Professional printing, archiving |
| RAW | None | N/A | Camera originals, editing |
For a 4×6 inch print at 300 DPI, you need 1200×1800 pixels = 2.16 megapixels. Most modern smartphone cameras (12MP+) capture far more than enough for standard print sizes. For a large 16×20 print at 300 DPI, you need 4800×6000 pixels = 28.8 megapixels.
Lossy compression (JPEG, WebP lossy) permanently removes some image data to reduce file size — the more you compress, the more quality you lose. Lossless compression (PNG, TIFF, WebP lossless) reduces file size without losing any image data — the original can be perfectly reconstructed. Use lossless for graphics and archiving, lossy for photos shared online.
A RAW file contains the unprocessed, uncompressed sensor data from your camera — all the information captured by each pixel. A JPEG is a processed, compressed version of that data. A 24MP RAW file can be 25–50 MB, while the same image as JPEG might be 5–8 MB. RAW files give more flexibility in post-processing but take up much more space.
Most social platforms display images at 72–96 DPI. For Instagram posts, 1080×1080 px (square) or 1080×1350 px (portrait) is ideal. For Facebook cover photos, 820×312 px. For Twitter/X headers, 1500×500 px. Always export at the exact pixel dimensions — DPI doesn't matter for screen display.