Image Size Calculator

Uncompressed raw size = Width (px) × Height (px) × Bit Depth ÷ 8 (bytes). This is the total pixel data without any compression, metadata, or file headers. For example, a 1920×1080 image at 24-bit depth = 1920 × 1080 × 24 ÷ 8 = 6,220,800 bytes ≈ 5.93 MB. This is what the image occupies in memory before being saved to a compressed format like JPEG or PNG.

JPEG uses lossy compression that dramatically reduces file size by discarding subtle color details the human eye can't easily perceive. Depending on quality settings (60%–100%), a JPEG can be 5–20 times smaller than the uncompressed version. At 85% quality, typical JPEG compression ratio is about 10:1 to 15:1, turning that 5.93 MB raw image into roughly 400–600 KB.

24-bit (True Color) uses 8 bits each for Red, Green, and Blue channels — producing 16.7 million colors. 32-bit adds an Alpha channel (8 extra bits) for transparency information. The alpha channel is used in formats like PNG-32 and WebP to support translucent pixels. For opaque images without transparency needs, 24-bit is sufficient and saves 25% raw size compared to 32-bit.

WebP is the modern recommendation — it offers both lossy and lossless compression, supports transparency, and produces files 25–34% smaller than JPEG/PNG equivalents. For photos, use JPEG or WebP (lossy). For logos, icons, or images with text/sharp edges, use PNG or WebP (lossless). For animations, WebP or GIF. Always serve responsive images using <picture> and srcset for optimal performance.

DPI (Dots Per Inch) only affects print dimensions, not the pixel file size. A 3000×2400 px image is always 3000×2400 pixels regardless of DPI setting. At 300 DPI, it prints at 10×8 inches. At 150 DPI, it prints at 20×16 inches (larger but less sharp). The DPI metadata tag simply tells the printer how to scale the pixels. For high-quality prints, 300 DPI is the industry standard.

One megapixel = 1,000,000 pixels. A 12MP camera produces images around 4000×3000 px (12 million pixels). This tool shows the MP value for any dimensions. For reference: Full HD (1920×1080) ≈ 2.07 MP, 4K (3840×2160) ≈ 8.29 MP, 8K (7680×4320) ≈ 33.18 MP. Higher MP means more detail and larger file sizes — but also more flexibility for cropping and large-format printing.

PNG uses lossless compression, meaning it preserves every pixel exactly. While it does compress data (using DEFLATE algorithm), the compression ratio is typically only 2:1 to 5:1 — much less aggressive than JPEG's lossy compression. A 32-bit PNG also stores the alpha channel, adding 33% more data compared to 24-bit. For photographic images where perfect pixel accuracy isn't required, JPEG or lossy WebP will always produce much smaller files.

Yes! Simply multiply your desired print size (in inches) by the DPI. For example, to print at 8×10 inches at 300 DPI, you need 2400×3000 pixels. Use this tool in reverse: enter those pixel dimensions and you'll see the uncompressed file size. For a 24×36 inch poster at 300 DPI, you'd need 7200×10800 pixels (about 77.8 MP), which results in roughly 222 MB of uncompressed data at 24-bit depth.