PNG & JPG to WebP Converter
Convert PNG and JPEG images to WebP locally with adjustable browser encoder quality.
Convert a local PNG or JPEG to WebP using the browser Canvas encoder, with adjustable quality and exact before/after byte comparison.
Use PNG & JPG to WebP Converter
Your browser does not support client-side WebP export via HTML5 Canvas. Conversion cannot proceed in this browser.
Single PNG or JPEG file up to 50 MB. 100% private in-browser conversion.
Ctrl / ⌘ + Enter to convert
Click "Convert to WebP" to render the WebP output
Built for the task, not the page view
- Adjustable browser WebP encoder quality control
- Original and converted preview with exact file-size change reporting
- Runtime detection of WebP canvas-encoding support
- PNG alpha-transparency handling where supported by the browser encoder
- Immediate local WebP download with object-URL cleanup
JPGJPEGPNGWebPUse it correctly
Browser Canvas WebP Encoding
This tool uses your browser’s native HTML5 Canvas toBlob("image/webp", quality) capability. Decoding and re-encoding occur entirely through local browser image and Canvas APIs without transmitting image bytes to a remote conversion server.
Configurable Quality (0.10 to 1.00)
The quality slider passes a value from 10% (0.10) to 100% (1.00) to the browser WebP encoder. Lower settings generally trade more image fidelity for smaller output, while higher settings generally retain more detail at a possible size cost. 80% is a convenient starting example, not a universal optimum—compare the actual output visually and by measured bytes.
Decoded Alpha Transparency Handling
Decoded PNG transparency (alpha channel) is drawn directly onto a clear canvas without adding an artificial white or black background. When the browser’s WebP encoder supports alpha compression, transparency is preserved in the exported WebP asset.
Real-Time Size Comparison Without Assumptions
Compression efficiency varies based on image complexity, original format, alpha transparency, and selected quality. Rather than promising arbitrary percentage reductions, this tool measures and reports exact input bytes, output bytes, byte delta, and percentage change. If a highly compressed source image results in a larger WebP file, the tool displays that increase honestly.
Single-Frame Decoded Frame Limitation
Canvas conversion produces one static rendered frame rather than preserving a multi-frame animation. For animated inputs, the exact decoded/rendered frame behavior can vary by browser and image-decoding API, so this tool should not be used when animation preservation matters.
Color Profiles & Browser Encoder Variability
Browsers vary in how their Canvas and image-decoding subsystems handle embedded ICC profiles, wide-gamut color, gamma, and color management. Exact ICC or Display-P3 profile preservation is not guaranteed after Canvas re-encoding, so color-critical workflows should verify the exported file in a color-managed application.
Single Image Workflow
This canonical tool focuses on single-file conversions with immediate visual comparison, exact byte counters, and parameter tuning. Bulk directory conversion will be supported through a dedicated workflow.
100% Client-Side Privacy Guarantee
Your images never leave your computer. All decoding, pixel processing, and WebP compression run entirely in browser memory. Analytics collects only fixed interface event identifiers, never image files, file names, or pixel data.
WebP Conversion FAQ
How does WebP improve Core Web Vitals and LCP?
Largest Contentful Paint (LCP) can be affected by the transfer and decode cost of a prominent image. If the WebP output is materially smaller at acceptable visual fidelity, using it can reduce image transfer bytes and may improve LCP. WebP is not automatically smaller for every source, so compare the measured output before replacing an existing asset.
What is the optimal WebP quality setting for websites?
There is no universal optimal quality setting because browser encoders and source images differ. A value around 80% is a practical starting example: convert once, inspect the result at the size it will actually be displayed, compare the measured bytes, and then move the slider higher or lower based on the fidelity/size tradeoff you observe.
Does converting PNG to WebP preserve transparency?
The tool keeps the Canvas background transparent rather than adding an artificial black or white fill. When the browser WebP encoder supports alpha output, transparency can be retained in the exported file; verify the converted preview/output when alpha fidelity is important.
Why can a WebP output sometimes be larger than the original?
If your source JPEG was already heavily compressed at a low quality setting with chroma subsampling, re-encoding it at a high WebP quality setting (e.g. 90%) can result in an output file with equal or larger byte size. This tool reports exact input and output bytes honestly so you can make data-driven decisions.