Image File Size Calculator

The calculator provides a theoretical estimate based on dimensions, bit depth, and compression ratio. Actual file sizes may vary due to several factors: the specific compression algorithm used by different software, the content of the image (complex images compress differently than simple ones), metadata included in the file, and additional formatting information specific to certain file types.

For web images, the best formats are typically:
- JPEG: For photographs and complex images with many colors
- PNG: For images that require transparency or have text, line art, or few colors
- WebP: A modern format that provides both better lossy and lossless compression than JPEG and PNG
- AVIF: The newest format with excellent compression and quality
Consider your specific needs for quality, compatibility, and file size when choosing a format.

Image resolution (the number of pixels per inch or PPI) doesn't directly affect file size for digital images. What matters is the total pixel dimensions (width × height). For example, a 1000×1000 pixel image will have the same file size whether it's set to 72 PPI or 300 PPI, as long as the total dimensions remain 1000×1000 pixels. Resolution only becomes relevant when printing, as it determines how densely those pixels are packed on physical media.

Bit depth refers to the number of bits used to represent each color channel (red, green, or blue) in a pixel. Color depth (or pixel depth) refers to the total number of bits used to represent color information for each pixel, which is the sum of the bit depths across all channels. For example, in standard RGB images, if each channel has an 8-bit depth, the color depth is 24 bits (8 bits × 3 channels), allowing for approximately 16.7 million colors.

The impact of compression on image quality depends on the type of compression:
- Lossless compression (PNG, lossless TIFF) preserves all image data and doesn't affect quality at all, but offers modest file size reduction.
- Lossy compression (JPEG, WebP) discards some image data to achieve smaller file sizes. At high quality settings (low compression), the loss may be imperceptible. As compression increases, artifacts become visible, such as blockiness, color banding, or blurring of fine details.
The type of image content also matters—photographs can generally withstand more compression than text or line art before visible quality degradation occurs.

To optimize image file size while maintaining acceptable quality:
- Resize images to the dimensions they'll actually be displayed at
- Use appropriate compression for your content (JPEG for photos, PNG for graphics)
- Experiment with quality settings to find the sweet spot
- Consider modern formats like WebP that offer better compression
- Remove unnecessary metadata
- Use specialized image optimization tools that analyze and optimize compression
For web images, you can often reduce JPEG quality to 70-80% with minimal visible quality loss while achieving significant file size reduction.

EXIF (Exchangeable Image File Format) data is metadata embedded in image files that contains information about the camera settings, date and time, location, and other details about how the photo was taken. EXIF data typically adds between 10-30 KB to an image file, which is negligible for larger images but can be significant for small, highly optimized web graphics. If file size is critical, you can remove EXIF data using image editing software or specialized tools.