B BLUESKY LABS

Calculator Tools

How to Use the File Size Calculator

Estimate uncompressed image size and compressed output size for JPG, PNG, WebP, and upload planning.

Updated 2026-06-07. Bluesky Labs tools are designed for browser-local workflows whenever the tool supports local processing.

When to Use This Tool

  • Estimating final file sizes for web images before compression.
  • Planning storage requirements for high-resolution photography uploads.
  • Comparing different image formats like JPG, PNG, and WebP.

Step-by-Step Workflow

  1. Open the tool

    Navigate to the File Size Calculator tool on the Bluesky Labs website.

  2. Enter inputs

    Enter the dimensions (width and height) of your target image.

  3. Choose settings

    Select the desired image format from the available options (JPG, PNG, or WebP).

  4. Enter inputs

    Input the desired quality level or compression ratio for the output.

  5. Run the action

    Review the calculated uncompressed size versus the estimated compressed file size.

Best Practices

  • Use the tool early in your design process to ensure images meet website performance standards.
  • Compare multiple formats (e.g., WebP vs. JPG) to find the best balance between quality and size.
  • Account for metadata overhead when planning very small file size requirements.
  • Use the estimates as a guide, as actual compression results may vary slightly based on image complexity.

FAQ

What is the difference between uncompressed and compressed size?

Uncompressed size represents the raw data of an image at full quality, while compressed size shows how much space it will occupy after applying format-specific algorithms.

Which format should I choose for the smallest file size?

WebP generally offers superior compression compared to JPG and PNG, making it an excellent choice for web optimization.