Calculate uncompressed and compressed file sizes for digital images based on resolution and color depth. Essential for photographers, web designers, and digital artists.
Last updated: March 2026 | By Patchworkr Team
Image file size is the amount of digital storage space required to save an image. It depends primarily on three factors: the image dimensions (width × height in pixels), the color depth (bits per pixel), and the compression method used.
An uncompressed image stores complete color information for every pixel. For example, a standard RGB image uses 24 bits (3 bytes) per pixel: 8 bits each for red, green, and blue channels. A 1920×1080 pixel image contains 2,073,600 pixels, requiring about 6.2 MB uncompressed.
Compression dramatically reduces file sizes. JPEG uses lossy compression (discarding some data) to achieve 90-95% size reduction, ideal for photographs. PNG uses lossless compression (preserving all data) achieving 50-80% reduction, perfect for graphics with sharp edges and text.
Calculate the file size of a Full HD image (1920×1080) in RGB format:
Megapixels (MP) measure the total number of pixels in an image (millions). MB (megabytes) measures the file size. A 10 MP image can range from 1 MB (highly compressed JPEG) to 30 MB (uncompressed RAW) depending on compression.
This calculator shows theoretical uncompressed sizes and typical compression estimates. Actual sizes vary based on image content complexity, compression quality settings, metadata (EXIF data), and the specific compression algorithm used.
Use JPEG for photographs and images with gradients—it offers excellent compression. Use PNG for images with text, sharp edges, transparency, or when you need lossless quality. PNG is larger but preserves every detail.
RAW is unprocessed data directly from a camera sensor. It's uncompressed or lightly compressed, preserving maximum image quality and editing flexibility. File sizes are much larger—typically 20-40 MB for modern cameras.
Color depth (bits per pixel) directly multiplies file size. Going from 8-bit grayscale to 24-bit RGB triples the file size. 32-bit RGBA adds an alpha channel, increasing size by 33% over RGB.
For web use, aim for 72-150 DPI at display size. A full-width banner might be 1920×600 pixels. For thumbnails, 300×300 is common. Always use JPEG or WebP compression to keep file sizes under 200 KB for fast loading.
Not always. More megapixels help for large prints or cropping, but sensor size, lens quality, and lighting matter more. A 12 MP camera with a great sensor often beats a 48 MP camera with a small, cheap sensor.
For photos, use JPEG quality 85-95% (not 100%)—visually identical but much smaller. For graphics, use PNG with optimization tools. Consider WebP format for 25-35% better compression than JPEG with similar quality.
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