Image File Size Calculator
Calculate the file size of digital images based on resolution, bit depth, and compression ratio. Estimate storage requirements and bandwidth needs for images.
1 = no compression, 10 = 10:1 compression (JPEG quality ~90)
How to Use This Calculator
- Enter your image dimensions in pixels (width and height).
- Select the bit depth (24-bit RGB is standard for most images).
- Enter the compression ratio (10:1 is typical for JPEG quality 90, adjust based on your format and quality).
- The calculator displays both uncompressed and compressed file sizes in bytes, KB, MB, or GB.
File Size Formula
Image file size is calculated from resolution, bit depth, and compression:
Compressed = Uncompressed ÷ Compression Ratio
Example: A 1920×1080 image at 24-bit with 10:1 compression: Uncompressed = (1920 × 1080 × 24) ÷ 8 = 6.22 MB. Compressed = 6.22 ÷ 10 = 622 KB.
Full Description
Understanding image file sizes is essential for photographers, web developers, and content creators. File size affects storage costs, website performance, upload/download times, and user experience. This calculator helps you estimate file sizes before creating or processing images, allowing you to plan storage needs and optimize for different use cases.
Uncompressed file size represents the raw data required to store the image without any compression. This is useful for understanding the theoretical maximum size and for formats like RAW or uncompressed TIFF. Compressed size accounts for compression algorithms like JPEG, which can reduce file sizes by 10-20x while maintaining acceptable quality for most uses.
Use this calculator to estimate storage requirements for photo libraries, plan website bandwidth needs, and understand how different resolutions and formats affect file sizes. Remember that actual compressed sizes vary based on image content—simple images compress better than complex, detailed ones.
Frequently Asked Questions
How is image file size calculated?
Uncompressed size = (Width × Height × Bit Depth) ÷ 8. Compressed size depends on the compression algorithm (JPEG, PNG, etc.) and quality settings. JPEG typically achieves 10:1 to 20:1 compression, while PNG uses lossless compression with variable ratios.
What bit depth should I use?
24-bit (RGB) is standard for most photography and web use. 32-bit includes an alpha channel for transparency. 16-bit is used for high-end photography and editing. 8-bit is sufficient for simple graphics but limited in color range.
How accurate is the compression estimate?
Compression ratios vary significantly based on image content. Simple images with large uniform areas compress better than complex, detailed images. JPEG quality 90 typically achieves 10:1 compression, quality 80 achieves 15:1, and quality 60 achieves 20:1.
Why do file sizes matter?
File size affects storage requirements, upload/download times, website loading speeds, and bandwidth costs. Understanding file sizes helps you optimize images for web use, plan storage needs, and estimate transfer times.