PNG compressor
Re-encode PNG for smaller files.
This runs in your browser. Nothing is uploaded.
About PNG compressor
Re-encodes a PNG losslessly in your browser, recovering whatever bytes the original encoder left on the table, which is sometimes a worthwhile saving and sometimes almost nothing.
PNG files that come out of screenshot utilities, design exports and older software often carry more bytes than they need: lazy compression settings, unnecessary chunks, an encoder that was not trying very hard. Running them through a stricter encoder recovers some of that without touching a single pixel. Screenshots, icons and flat-colour graphics tend to benefit most.
This is a lossless re-encode. The file is decoded to raw pixels and written back out through a WebAssembly PNG encoder that compresses the pixel data harder than most export tools bother to. Every pixel value in the output is identical to the input, transparency included. All the saving comes from better compression of the same data, so it depends entirely on how sloppy the original encoder was.
Set your expectations accordingly. This is not a lossy PNG optimiser — there is no colour quantisation, no palette reduction, no dropping of the alpha channel, and no quality dial to turn, because lossless compression does not have one. On a photograph saved as PNG you may save nothing at all. Converting to WebP is the real answer there.
How to use PNG compressor
- 1Drop your PNG onto the panel or click to browse.
- 2Click Compress & download.
- 3Compare the output and input sizes printed underneath. If the saving is negligible, try converting to WebP instead.
What it won't do
- There is no quality setting, because the re-encode is lossless and has nothing to trade away.
- No colour quantisation or palette reduction, so do not expect pngquant-sized savings.
- On photographs the saving is often negligible, and occasionally zero.
Common questions
Can you compress a PNG without losing quality?
Yes, and that is exactly what happens here. PNG compression is lossless by design, so a re-encode changes how the pixel data is stored without changing any pixel values. The trade-off is that lossless savings are modest: typically 5 to 25 percent on graphics and screenshots, and often close to zero on photographs.
Why did my PNG barely get smaller?
Because whatever produced it already compressed it well. Lossless optimisation can only find redundancy the previous encoder missed, and modern export tools do not leave much behind. Photographs are the worst case — fine noise in every pixel gives the compressor almost no repetition to work with. Converting a photographic PNG to WebP or AVIF will cut it far more.
Does this reduce the number of colours in my PNG?
No. There is no palette reduction or colour quantisation here, which is what tools like pngquant do to reach their dramatic numbers. Those results are lossy: they throw away colour information and can band smooth gradients. This keeps the image bit-for-bit identical, which is the right default for a logo, an icon or a UI asset.
Does it keep transparency?
Yes. The alpha channel comes through exactly, since nothing about the image data changes. That is the main reason to compress a PNG rather than convert it to JPEG, which has no transparency at all. If changing format is acceptable, WebP keeps transparency and compresses considerably harder.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation