Compress
Compress a PNG
PNG is a lossless format, so there is no quality dial to turn down.
The way to make a PNG genuinely smaller is to reduce how many distinct colours it contains, which is exactly what this tool does - while keeping the transparent background intact.
How to compress a PNG
- Drop one PNG file or a whole folder of them onto the upload area.
- Choose how many colours to keep. Fewer colours means a smaller file.
- Turn on dithering if you see banding in gradients.
- Download the compressed PNG.
Supported formats
This tool accepts PNG files. Everything is decoded by your own browser, so the formats available depend on what your browser can open - which for HEIC in particular varies between Safari and other browsers.
Because the image is rebuilt from raw pixels, EXIF metadata such as camera details, timestamps and GPS coordinates does not carry into the result. Orientation is applied to the pixels first, so photographs stay the right way up. Embedded colour profiles are also dropped and the output is saved as sRGB, which can shift colours slightly in wide-gamut photographs. Animated files are refused rather than being flattened to a single frame.
Frequently asked questions
Is my PNG uploaded anywhere?
No. PNG files are often screenshots of private things - dashboards, invoices, messages - so this is worth being precise about. The file is opened and rewritten inside your browser tab and no part of it is transmitted.
Is the PNG compressor free?
Yes. There is no sign-up and no watermark added to the output. The PNG you download is exactly what the tool produced.
How does PNG compression work here?
PNG stores pixels losslessly, so it cannot simply be re-saved smaller. This tool reduces the number of distinct colours in the image using median-cut quantisation. Fewer colours means less variation for the PNG encoder to describe, which is what actually shrinks the file - often by 60-70% at 128 colours.
Is transparency preserved?
Yes. The alpha channel is left completely untouched, so soft edges, drop shadows and cut-out backgrounds survive exactly as they were. Only the colour channels are quantised.
What is dithering and should I turn it on?
Dithering scatters small variations between neighbouring pixels so that a reduced palette still looks smooth. Turn it on for photographs and gradients, where flat colour bands would otherwise be visible. Leave it off for logos, icons and screenshots, which look cleaner and compress better without it.
How many colours should I keep?
256 is nearly indistinguishable from the original for most images. 128 is a good balance. 64 or fewer works well for logos, icons and flat illustrations but will show banding on photographs.
Should I use PNG or WebP?
WebP supports transparency too and is usually far smaller than PNG for the same visual quality. If the image is for the web and you do not need PNG specifically, converting to WebP will almost always beat compressing the PNG.
Guides
- How to compress an image without losing qualityFor photographs, use JPEG at quality 80-90, or convert to WebP. You will typically save 60-80% with no difference visible at normal viewing size. Genuinely lossless compression only saves about 5-20%, and only for PNG.
- Why PNG files are so largePNG is lossless: it stores every pixel exactly, so it cannot throw away detail to save space. To make one smaller, either reduce how many distinct colours it stores - which is lossless for what remains and very effective on screenshots - or convert to JPEG or WebP if the image is a photograph.
Related tools
- Image CompressorCompress JPG, PNG and WebP images in your browser.
- WebP CompressorCompress WebP images in your browser with a quality slider or a target file size.
- PNG to JPG ConverterBatchConvert PNG images to JPG in your browser with control over quality and background colour.
- JPG CompressorShrink JPG and JPEG photos in your browser.
- PNG to WebP ConverterBatchConvert PNG to WebP with no loss at all.
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