01
Image Compressor
Compresses images to a target quality or file size in your browser, with a live…
Image Format Size Comparer
Encodes the same image as JPEG, WebP, AVIF and PNG at one quality setting and shows the real byte counts side by side.
Image
Nothing uploaded
No sign-up
Free, unlimited
Drop an imageencoded four ways in this page — nothing is uploaded
Add a file to begin.
In short
On photographs the usual ordering by size is AVIF smallest, then WebP, then JPEG, with PNG largest — but PNG is lossless and the other three are not, so PNG being biggest says nothing about its quality. As a rough guide at matched quality, WebP saves around 25–35% against JPEG and AVIF around 40–50%. The comparison only means anything on your own images: a flat graphic with few colours behaves completely differently from a photograph, and PNG can beat all three on line art. This tool encodes your image in every format the browser genuinely supports and reports the real sizes, marking AVIF unavailable rather than reporting a PNG in its place.
How to use the Image Format Size Comparer
- Drop in a representative image.
- Set one quality for all the lossy formats.
- Read the ranking rather than the absolute numbers.
About the Image Format Size Comparer
The Image Format Size Comparer encodes the same image as JPEG, WebP, AVIF and PNG at one quality setting and shows the real byte counts side by side. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Deciding which format to serve for a particular image.
- Showing a client what AVIF is worth on their photographs.
- Checking whether PNG is genuinely the right choice for a graphic.
Details
| Typical, photographs | AVIF < WebP < JPEG < PNG |
|---|---|
| Typical, flat graphics | PNG can beat the lossy formats outright |
| WebP against JPEG | Roughly 25–35% smaller at matched quality |
| AVIF against JPEG | Roughly 40–50% smaller |
| Transparency | JPEG has none; the other three do |
The result depends far more on the image than on the format. A photograph of foliage, a flat logo and a screenshot of text will each rank the formats differently, which is exactly why a general "AVIF is 50% smaller" figure is worth so little compared with testing your own.
Where this tool stops
Uses the browser's built-in encoders at their default effort. Dedicated command-line encoders given time will produce smaller files in every format, so treat these as a fair comparison rather than as best-achievable sizes.
Frequently asked questions
Why is PNG always the largest?
Because it is lossless — it stores every pixel exactly while the others discard what they judge invisible. Comparing PNG on size against three lossy formats is not a fair fight, and it does not mean PNG is the wrong choice. For line art, screenshots and flat graphics, PNG is often both smaller and better.
AVIF shows as not supported. Is my image the problem?
No — your browser is. Asking a canvas for AVIF where the encoder is missing returns a PNG with no error, so this tool marks it unavailable rather than reporting that PNG's size as AVIF's. Any comparison table without that check is quietly wrong about AVIF. Chrome and Edge can encode it.
Should I just serve whichever wins here?
Serve it first, with fallbacks beneath. A <code><picture></code> element with AVIF, then WebP, then JPEG gives every browser the best format it understands. Serving only the winner means the browsers that cannot read it get nothing.
Is the Image Format Size Comparer free, or is there a paid tier?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is what I paste into the Image Format Size Comparer stored?
No. The Image Format Size Comparer runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
What is the Image Format Size Comparer used for?
The jobs it is built for: deciding which format to serve for a particular image. Showing a client what AVIF is worth on their photographs. Checking whether PNG is genuinely the right choice for a graphic. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
What are the limits of the Image Format Size Comparer?
Uses the browser's built-in encoders at their default effort. Dedicated command-line encoders given time will produce smaller files in every format, so treat these as a fair comparison rather than as best-achievable sizes. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the reference figures here?
Typical, photographs is AVIF < WebP < JPEG < PNG. Typical, flat graphics is PNG can beat the lossy formats outright. WebP against JPEG is Roughly 25–35% smaller at matched quality. These are printed on the page itself, so you do not have to take them on trust.
Will a big file be rejected?
There is no limit set by us, because your file is never uploaded — the only ceiling is the memory your own browser will give the tab. Very large files simply take longer to process, and a phone will give up sooner than a desktop.
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