PNG to WebP — Free Online Batch Converter, Keeps Transparency, Nothing Uploaded
The point of converting PNG to WebP is to shrink the file without giving up transparency. PNG is lossless and a safe home for screenshots, icons and artwork with transparent backgrounds, but it tends to be oversized for photos and broad gradients. WebP supports both lossy compression and an alpha channel, so the same visual impression usually costs 20–30% less bandwidth, or more, and pages load faster. Set the quality slider yourself: higher values keep more detail and produce larger files, and around 0.8 is generally the balance point. The maximum-quality option pushes the parameter to 1, preserving more detail, but it is still near-lossless rather than true lossless WebP. You can also set rotation, flipping, a long-edge limit and shared filename prefixes and suffixes, and change the output format of any single image in a batch. On the right, compare side by side or with the split slider; the checkerboard shows whether transparent edges were smeared, and the info panel lists the source format, dimensions, size and output size together. Results can be downloaded one at a time, packed into a ZIP, copied as an image or as Base64, or recorded in a CSV list. Very old Safari versions and legacy image viewers do not read WebP, so save a JPG copy when sending files to other people. Everything runs locally in your browser: images are never uploaded and it keeps working offline.
Import images
Target format
The options below switch automatically when you pick a format.
Higher values look better but produce larger files; 0.8 to 0.9 is usually enough for photos.
WebP supports both lossy encoding and transparency, and is typically 20–30% smaller than a JPG of similar quality. The canvas encoder offers lossy settings only: quality 1 is near-lossless, not libwebp's real lossless mode.
The target format supports transparency, so transparent areas are preserved.
Very old Safari versions and some legacy software do not read WebP. Choose JPG when sharing with others or targeting old systems.
Basic adjustments
0 keeps the original size. Only shrinks, never enlarges — this is not a full resize tool.
Re-encoding in the browser automatically strips EXIF metadata such as capture time, GPS and camera model, which is safer by default. Portrait photos from phones are auto-rotated from their EXIF orientation first.
File naming
Example：photo_converted.webp
A few honest notes about format conversion
- Conversion always re-encodes the pixels, it is not just renaming the file. Renaming .png to .jpg may still open in some viewers, but uploads, moderation and programmatic parsing often break.
- Lossy output cannot be reversed. Detail and transparency lost in a PNG → JPG conversion will not come back if you convert it to PNG again, so keep your originals.
- Animated images keep only their first frame. Static JPG, PNG and WebP exports all take frame one; use a GIF tool to preserve animation.
- Everything runs locally in your browser. Images are never uploaded, and the tool keeps working offline.
Preview & export
Batch list
After importing several images, their status and size change will appear here.
How to use
- Drag your PNG images onto the page, click Choose images to import several at once, press Ctrl+V to paste a screenshot, or paste a link into the Image URL field. The tool reads the real format from the file header, so a misnamed file is still recognised.
- Start with the quality slider around 0.8 and check the size, then nudge it either way: push a photo too hard and flat colour blocks appear, while screenshots and icons need watching for softened text edges. For transparent artwork, turn on the checkerboard and check whether edges were smeared.
- Tick Maximum quality (near-lossless) to keep as much detail as possible, accepting a larger file. You can also set rotation, flipping, a long-edge limit, or a shared prefix and suffix for the whole batch — and change the output format for one image in the batch list.
- Wait for the converted preview on the right, compare it side by side or with the split slider, then download. Multiple images can be packed into a ZIP or listed in a CSV report; if the recipient uses a very old system, save an extra JPG copy.
Frequently asked questions
Does my transparent PNG background survive the WebP conversion?
Yes. A WebP container can carry its own alpha channel, so transparent areas, semi-transparent feathered edges and rounded corners are not filled with white or black. Turn on the checkerboard to check: wherever it shows through is still transparent. Only a JPG conversion requires choosing a fill colour, because JPG has no transparency dimension at all.
Is Maximum quality (near-lossless) real lossless WebP?
No. The canvas API in a browser exposes only a lossy encoder; setting quality to 1 still produces a lossy result, just one whose losses are hard to see. libwebp does have a separate lossless mode and a near-lossless parameter, but browsers do not expose that configuration to JavaScript, and this tool does not ship a WASM codec build — so we do not label it lossless. For strictly lossless WebP, use a desktop tool that supports that mode.
Is a WebP always smaller than the original PNG?
Not always. Flat-colour icons, line art and text screenshots are already extremely compact under PNG's lossless compression; a lossy WebP may be only slightly smaller, or even larger because the edges have to be described again. The biggest wins come from photos, gradient backgrounds and heavily textured artwork, commonly 20–30% or more. The info panel shows both sizes and the percentage, so check the numbers before deciding to keep that version.
What if the person I send the WebP to cannot open it?
Very old Safari versions, some legacy office suites and certain print systems genuinely cannot read WebP. On a website, pair it with a picture element and a JPG fallback. For sending directly by message or email, or feeding an older system, the simplest route is to unlock the target format here and save an extra JPG. Recent mainstream browsers, Android and current iOS all support it.
Are phone photos oriented correctly, and is EXIF preserved?
They are oriented correctly. Phones often store portrait shots as landscape pixels with an EXIF orientation flag; decoding straightens the image from that flag before conversion starts. The re-encoded WebP is a brand-new file, and capture time, GPS, camera model and similar metadata are stripped automatically, saving a little space and removing one privacy concern. If you genuinely need the original metadata, keep the source file.
What is it
PNG stores every pixel losslessly, which means all the tiny colour variations in a photograph or a broad gradient must be written down one by one. WebP borrows intra prediction from video coding: it guesses each block from already-decoded neighbours and sends only the prediction error through a transform and an entropy coder, so the same picture needs far fewer bits. Its container can also carry a separate alpha payload, so transparent edges are not forcibly flattened onto a solid colour the way they are in a JPG conversion. One caveat: the canvas encoding interface exposed to web pages offers only lossy settings. Even quality 1 is merely close to lossless; strictly lossless WebP requires bringing a compiled libwebp build into the page.
Origin & history
The timeline starts in 2010. The year before, Google acquired the video codec company On2 Technologies and with it the VP8 technology; in September 2010 Google released WebP, built on VP8's intra-frame coding and wrapped in a RIFF container. That ancestry matters. VP8 was designed for video keyframes and is good at predicting the current block from already-decoded neighbours, coding only the residual, then combining a transform with a boolean arithmetic coder — which compresses the repetitive local structure of a still image very effectively. The first WebP was lossy only; an extended format with an alpha channel arrived in 2011, and around 2012 came the separate lossless VP8L codec plus metadata and animation support. The open-source libwebp reference implementation was adopted by Chromium, Android and a great many server-side toolchains. PNG, meanwhile, was already about fifteen years old: a W3C Recommendation in 1996 and ISO/IEC 15948 in 2003, firmly holding icons and screenshots through losslessness and transparency, but never offering an efficient path for photographs. The biggest obstacle to WebP was not the algorithm but the ecosystem. Chrome supported it early, Firefox only caught up with version 65 in 2019, and Safari waited until iOS 14 and macOS Big Sur in 2020. For the years in between, front ends relied on picture elements or servers negotiating by request headers, keeping two files for one image. That is why PNG to WebP became a fixture on every website optimisation checklist. Once browsers brought the job local, the HTML5 canvas toBlob method accepted image/webp with a quality argument, backed by the browser's own lossy libwebp path, and createImageBitmap added EXIF-aware decoding so portrait phone photos come out straight. The boundary worth remembering is that libwebp's lossless mode and near_lossless parameter are advanced settings the web interface does not expose, so an in-browser conversion produces lossy WebP. That limitation does not stop it saving sites a great deal of bandwidth, but it does mean any claim of lossless WebP from a web page deserves a second question.
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