Quick Answer

A 1920x1080 image at 24-bit color (RGB) has a raw size of 5.93 MB. Saved as JPEG at quality 80, the estimated file size is approximately 593 KB. As WebP, it is approximately 395 KB.

Image Dimensions

Width (px)

Height (px)

Format Settings

Color Depth 24-bit (RGB) 32-bit (RGBA) 8-bit (Grayscale)

Format JPEG PNG WebP AVIF GIF BMP TIFF

Quality: 80%

Common Examples

Input	Result
1920x1080, 24-bit RGB, JPEG quality 80	Approximately 593 KB
1920x1080, 24-bit RGB, PNG	Approximately 1,977 KB
1920x1080, 24-bit RGB, WebP quality 80	Approximately 395 KB
800x600, 32-bit RGBA, PNG	Approximately 625 KB
4000x3000, 24-bit RGB, JPEG quality 60	Approximately 720 KB

How It Works

An uncompressed image stores a fixed number of bits per pixel. The raw size formula is:

Raw Size (bytes) = Width x Height x Color Depth / 8

Where color depth is the number of bits per pixel:

• 8-bit: Grayscale (256 shades of gray)
• 24-bit: RGB color (8 bits each for red, green, blue; 16.7 million colors)
• 32-bit: RGBA color (24-bit RGB + 8-bit alpha transparency)

Compression ratios by format

Image formats reduce file size through compression. Approximate ratios at typical quality settings:

• JPEG: ~10:1 (lossy, no transparency, best for photographs)
• PNG: ~3:1 (lossless, supports transparency, best for graphics and screenshots)
• WebP: ~15:1 (lossy or lossless, supports transparency, modern web standard)
• AVIF: ~20:1 (lossy or lossless, newest format with best compression)
• GIF: ~5:1 (lossless, limited to 256 colors, supports animation)
• BMP: ~1:1 (uncompressed)
• TIFF: ~1.5:1 (minimal compression, used in print)

How quality affects file size

For lossy formats (JPEG, WebP, AVIF), lower quality means higher compression and smaller files. At quality 100, compression is minimal (roughly 3-4:1 for JPEG). At quality 50, compression increases significantly (roughly 15-20:1 for JPEG). Quality 70-85 is the typical sweet spot, balancing visual quality and file size.

For lossless formats (PNG, BMP, GIF), the quality slider has little to no effect because the compression is determined by the image content rather than a quality setting.

Worked Example

For a 1920x1080 image at 24-bit RGB saved as JPEG at quality 80: Raw size = 1920 x 1080 x 24 / 8 = 6,220,800 bytes = 6,075 KB = 5.93 MB. JPEG compression ratio at quality 80 is approximately 10:1. Estimated file size = 6,075 / 10 = approximately 608 KB. Actual file sizes vary based on image content. Photographs with complex detail compress less than images with large areas of uniform color.

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Frequently Asked Questions

Why does the actual file size differ from the estimate?

Compression efficiency depends heavily on image content. Photographs with gradients and complex textures compress less efficiently than graphics with large areas of solid color. These estimates use average compression ratios. Actual file sizes can vary by 30-50% depending on the specific image.

Which image format should I use for the web?

For photographs, use WebP (best compression) or JPEG (widest compatibility). For graphics, logos, or images with transparency, use WebP or PNG. AVIF offers even better compression than WebP but has less browser support as of 2025. Use the HTML <picture> element to serve WebP/AVIF with JPEG/PNG fallbacks.

What is the difference between lossy and lossless compression?

Lossy compression (JPEG, WebP lossy) permanently removes some image data to achieve smaller files. The removed detail is not recoverable. Lossless compression (PNG, WebP lossless, GIF) reduces file size without losing any image data. The original image can be perfectly reconstructed. Lossy formats produce much smaller files but with some quality loss.

What quality setting should I use for web images?

A quality setting of 75-85 provides a good balance for most web images. Below 70, compression artifacts (blockiness, color banding) become visible in JPEG. Above 85, file size increases significantly with minimal visual improvement. For WebP, a quality of 75-80 typically matches JPEG at quality 85.

How does color depth affect file size?

Color depth determines how many bits are stored per pixel. A 32-bit RGBA image is 33% larger than a 24-bit RGB image because of the extra 8-bit alpha (transparency) channel. An 8-bit grayscale image is one-third the size of a 24-bit RGB image. If your image does not need transparency, saving as 24-bit RGB instead of 32-bit RGBA reduces file size.