Compress a PNG file without losing any quality. This tool uses lossless optimization, which removes redundant data from the PNG encoding so you get a smaller file with pixel-identical output.
It's completely free and runs locally in your browser.
How to use this tool
Add your PNG
Drag and drop your PNG or choose it from your files.
Lossless PNG is pre-selected
The output is already set to lossless PNG. Leave the quality at its default to keep every pixel identical.
See the savings
The tool shows your original size next to the compressed size.
Download
Download your losslessly compressed PNG.
What "lossless PNG compression" actually does
Lossless compression does not touch a single pixel. It reduces the file by encoding the same image data more cleverly — choosing better PNG filter types per scanline, and applying a stronger DEFLATE pass over the result. Every pixel of the output is identical to the input, byte for byte after decoding.
Typical savings are 10–30% for photographic PNGs and rather less for images that are already well optimised, because a PNG that has been through a good encoder once has little redundancy left to find.
How to tell it worked
Compare file sizes, not pixels. If the output is smaller and the image looks identical at 100% zoom, it worked. Because the process is lossless, there is no quality slider to worry about and no such thing as "too aggressive" — the only variable is how long the encoder is allowed to search.
If lossless is not enough
When the file is still too large after lossless optimisation, the choice is between accepting some quality loss and reducing the image itself. In order of how little they hurt: reduce the pixel dimensions to what is actually displayed, reduce the colour depth if the image has few colours, then move to a lossy format such as WebP or JPEG.
Resizing is almost always the bigger win. A 3000-pixel-wide PNG displayed at 800 pixels is wasting more bytes than any encoder setting can recover.
Frequently asked questions
How much can a PNG be compressed without losing quality?
Typically 20–50% depending on the image. Images with large flat areas compress more than noisy photographs.
Is 'lossless' really no quality loss?
Yes. Lossless compression means the decoded image is bit-for-bit identical to the original.
Why is my PNG already small?
If your PNG was already optimized, there may be little left to save. The tool always shows the honest result.