Digital Image & Print Size Calculator
Calculate uncompressed file size and physical print dimensions.
Calculated Results
Understanding Digital Image Resolution
Whether you are a professional photographer or a hobbyist, understanding the relationship between pixels, bit depth, and file size is crucial for managing your storage and preparing images for print. This photo calculator helps you translate digital dimensions into real-world metrics.
How Image File Size is Calculated
The "true" uncompressed size of a digital image is determined by the total number of pixels and the amount of data stored for each pixel. The formula used by our calculator is:
File Size (Bytes) = (Width × Height × Bit Depth × Number of Channels) / 8
- Pixels: The individual dots of color that make up an image.
- Bit Depth: Determines how many colors can be represented. 8-bit is standard for web, while 16-bit is common for professional editing to avoid "banding."
- Channels: Standard digital images use RGB (Red, Green, Blue), which is 3 channels. Professional printing often uses CMYK (4 channels).
PPI vs. DPI: What You Need to Know
PPI (Pixels Per Inch) refers to the resolution of a digital image, while DPI (Dots Per Inch) refers to the physical density of ink droplets on a printed page. For a high-quality "gallery grade" print, 300 PPI is generally considered the industry standard. Lowering the PPI allows for larger prints but reduces the sharpness when viewed up close.
Common Image Size Examples
- 4K Resolution: 3840 x 2160 pixels (approx. 8.3 Megapixels).
- Standard DSLR (24MP): 6000 x 4000 pixels. At 300 PPI, this yields a 20″ x 13.3″ high-quality print.
- Social Media: Instagram typically displays images at 1080 pixels wide.
Compression and File Formats
It is important to note that the "Uncompressed" size is what the image takes up in your computer's RAM while being edited. Formats like JPEG use lossy compression to significantly reduce the size on your hard drive, often by a factor of 10 or more, without a massive loss in perceived quality.