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Image File Size Calculator

Quick answer: Uncompressed size = width × height × bytes per pixel. A 4000×3000 photo at 24-bit colour is about 34 MB before compression.

About the Image File Size Calculator

Calculate image file size from dimensions, colour depth and compression. Free estimator.

JPG and WebP shrink that raw size by roughly 10–20× depending on quality.

Everything is calculated or processed in your browser, so nothing is uploaded.

How to use it

  1. 1Enter the numbers you know.
  2. 2The answer updates as you type.
  3. 3Copy the result.

Why use this tool

Private by design

Your files are processed on your device and never uploaded.

Free, no signup

No account, no watermark and no daily limit.

Instant

Results update as you change settings, with no waiting for a server.

Works on phone and desktop

A responsive layout that fits any screen.

Frequently asked questions

Why is my JPG smaller than the calculated size?

The calculator shows raw data. JPG compresses it a lot, so use the compression ratio to estimate the real file.

Are my images uploaded to a server?

No. PixTools processes images locally in your browser using your device. Your files are not uploaded or stored.

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