How to Compress PNG Without Losing Quality
Why are PNG files so large?
PNG uses lossless compression — every single pixel is stored exactly as it appears. This is why PNG produces perfect quality images with no compression artefacts. However, this precision comes at a cost — PNG files are significantly larger than JPG or WebP files for photographic content.
Furthermore, PNG file size depends heavily on image complexity. A simple flat-colour logo compresses very efficiently as PNG. In contrast, a photograph saved as PNG contains millions of unique pixel values that compress poorly. As a result, photos saved as PNG can be 5–10 times larger than the equivalent JPG.
A typical 3MB PNG photograph can be reduced to approximately 400–600KB as a compressed WebP at equivalent quality — a reduction of over 80%. Even lossless PNG compression typically reduces file size by 20–40% without any quality loss.
Three methods to compress PNG without losing quality
How to compress PNG online free — step by step
Our free image compressor handles PNG compression directly in your browser. Nothing is uploaded to any server — all processing happens locally on your device. Here is how to compress PNG files online:
Open the image compressor
Go to our free image compressor. It works on any device with no installation required.
Upload your PNG files
Drag and drop your PNG images or click to browse. You can upload multiple PNG files at once for bulk compression.
Choose output format
Keep PNG to compress while preserving transparency, or select WebP for even smaller files that also support transparency. Avoid JPG if your PNG has a transparent background.
Set quality level
For PNG output, set quality to 85–90% for near-lossless results. For WebP output, 80–85% gives excellent results with significant file size reduction.
Download compressed files
Click Compress and download your optimised PNG or WebP files instantly. Compare the before and after file sizes to see the reduction achieved.
Lossless vs lossy PNG compression — which to use?
Choosing between lossless and lossy PNG compression depends on the image type and intended use:
Use lossless PNG compression when:
- Archiving original files — keep source PNG files at full quality for future editing
- Images with text or sharp edges — lossy compression can create visible artefacts around text and sharp geometric shapes
- Logo source files — master logo files should be kept at perfect quality
- Medical or scientific images — any context where pixel-perfect accuracy is required
Use lossy PNG compression when:
- Web graphics and icons — the file size reduction is significant and quality loss is minimal on screen
- Social media images — platforms often recompress images anyway, so starting with lossy compression is fine
- Any image where file size matters more than perfect quality — for most web use cases, lossy compression at 85%+ is indistinguishable from lossless
Always keep your original PNG at full quality and compress a copy for web use. This way, if you need to make edits or create a higher quality version in the future, you still have the original to work from. Furthermore, never compress an already-compressed PNG — each generation of compression introduces additional quality loss.
Compress PNG vs convert PNG to WebP
For web use, converting PNG to WebP almost always produces better results than simply compressing the PNG. Here is a direct comparison:
- File size — WebP is typically 30–50% smaller than the best compressed PNG at equivalent visual quality. As a result, WebP pages load significantly faster.
- Transparency — both PNG and WebP support full alpha transparency. Therefore, logos and graphics with transparent backgrounds work perfectly in both formats.
- Quality — at equivalent compression settings, WebP maintains better quality than lossy-compressed PNG because of its more modern compression algorithm.
- Browser support — WebP is supported by all modern browsers including Chrome, Firefox, Safari 14+, and Edge. Over 97% of web users can view WebP.
- Compatibility — PNG has universal compatibility including older browsers, email clients, and all software. WebP may not work in some older or niche contexts.
In summary, use WebP for all web images where file size matters. Keep PNG when you need universal compatibility or are archiving source files. For more details, see our complete image format comparison.
Frequently asked questions
Can you compress PNG without losing quality?
Yes — lossless PNG compression reduces file size by 20–40% without changing a single pixel. The compressed file is mathematically identical to the original. For greater compression, lossy methods reduce file size by 60–80% with minimal visible quality loss at high quality settings of 85%+.
Why is my PNG file still large after compression?
If your PNG remains large after lossless compression, the image likely contains photographic content with high colour complexity. Photographs compress poorly as PNG regardless of the compression level. In this case, either use lossy PNG compression or convert to WebP or JPG for dramatically smaller files.
Does compressing PNG affect transparency?
No — both lossless and lossy PNG compression preserve the transparency (alpha channel) of PNG images. If you convert to WebP, transparency is also fully preserved. However, if you convert to JPG, transparency is permanently lost and replaced with a solid background colour.
What is the best PNG compression tool online?
Our free image compressor is one of the best PNG compression tools online because it processes everything locally in your browser — your files never leave your device. In addition, it supports bulk compression, multiple output formats, and adjustable quality settings, giving you full control over the compression result.