Convert PNG to WebP for Faster Page Loads
Convert PNG to WebP in your browser. WebP is two different codecs sharing one extension — lossless and lossy — and choosing the right one is the whole job, so this page makes the choice explicit.
Your images never leave your device
Nothing to delete later
Safe for screenshots
Works in every modern browser
How it works
- 1
Add your PNGs
Drop the files onto the page or click to browse and select them.
- 2
Choose lossless or lossy
Lossless for graphics and screenshots, lossy with a quality setting for photographs.
- 3
Download
Save the WebP files individually or all at once as a zip.
Why use this tool
Lossless mode keeps every pixel
WebP has a genuinely lossless codec that usually beats PNG by a quarter on the same image, with nothing thrown away.
Lossy mode keeps transparency
Unlike JPEG, lossy WebP has an alpha channel, which is what finally makes a cut-out product photo small.
The mode is your decision
A screenshot and a photograph want opposite settings, so the switch is on the page rather than hidden in a default.
Dimension limit checked
WebP cannot exceed 16383 pixels on a side, and an oversized image is caught before the encode fails.
Both sizes compared
The PNG and the WebP are shown side by side, because sometimes the saving is not worth the compatibility.
Nothing is uploaded
PNG is the screenshot format, and a screenshot shows more of your screen than you meant to capture.
WebP is two codecs wearing the same file extension
Almost every confusion about WebP comes from a fact the name hides: there is no single WebP compression. A .webp file may contain a VP8 bitstream, which is a still frame from a video codec and is lossy in exactly the way JPEG is, or it may contain a VP8L bitstream, which is a completely different algorithm designed from the start to be lossless and to compete with PNG. They share a container and an extension and nothing else. Nobody can tell which one a file holds by looking at its name, and that is why advice about WebP is so often contradictory — someone who converted a screenshot with the lossy encoder and someone who converted the same screenshot with the lossless one had opposite experiences and both blamed the format. Converting a PNG therefore starts with a decision rather than a click. Get it right and the result is smaller with no loss at all. Get it wrong and you have destroyed a diagram to save a few kilobytes.
Lossless WebP is one of the few conversions that is a pure win
It is worth saying plainly because most format conversions involve a trade, and this one largely does not. VP8L, the lossless WebP codec, does the same job as PNG but with better tools. Where PNG applies one of five simple filters per row and then hands the result to a general-purpose compressor, WebP uses spatial prediction with fourteen modes chosen per block, a colour cache that recognises recently used pixels, a colour transform that decorrelates the channels, and a palette stage when the image has few colours. The typical result on the same image is twenty to thirty per cent smaller, and on flat graphics with large uniform areas it can be far more. Nothing is discarded: decode the WebP and you get back exactly the pixel values the PNG held, alpha included. If you are serving images on the web and your only concern is size, lossless WebP replaces PNG with no argument to be had about quality.
Lossy WebP solved a problem that had no answer before
There used to be a category of image with no good format. A photograph with a transparent background — a product shot cut out from its studio backdrop, a person masked from a scene, a rendered object dropped onto a page — needs both photographic compression and an alpha channel. JPEG has excellent photographic compression and no alpha at all. PNG has perfect alpha and compresses photographs terribly, because its lossless algorithm cannot exploit the fact that a photograph is mostly smooth noise. The usual answer was a PNG of several megabytes for a single product image, which is why online shops were heavy for years. Lossy WebP is the format that closed the gap: VP8 compression for the colour channels, a separate alpha plane, one file. A cut-out product photo that was four megabytes as a PNG is often under two hundred kilobytes as a lossy WebP, and this is the single strongest reason to convert.
The 16383-pixel wall, and the files that hit it
WebP has a hard maximum dimension that surprises people because PNG effectively has none. No side of a WebP image may exceed 16383 pixels — a limit that comes from the VP8 bitstream, which allocates fourteen bits to each dimension. PNG allows just over two billion pixels per side, so anything that fits in memory fits in a PNG. Most images never approach the limit, but a specific set of them do, and they are exactly the kind of thing people convert in bulk. Full-page screenshots of long documents or long web pages routinely run to twenty or thirty thousand pixels tall. Stitched panoramas exceed it horizontally. Scanned posters, architectural drawings and large-format maps at print resolution exceed it in both directions. When the encoder meets one of these it does not degrade gracefully; it refuses. This page checks the dimensions before encoding and tells you, so an oversized image is reported rather than appearing as a mysteriously missing output file.
Converting away from PNG is a compatibility downgrade, and that is worth counting
PNG is about as universally readable as a file format gets. It has been supported everywhere since the late nineteen-nineties, it is royalty-free by design, and there is essentially no software that opens images and refuses it. WebP is younger and its support, while now very broad in browsers, thins out as soon as you leave them. Email clients are the sharpest edge: several widely used ones will not display a WebP in a message body, so a newsletter built with WebP images shows a broken-image icon to a meaningful share of recipients. Older desktop editors, many print and prepress workflows, some content management systems and a good number of upload forms still reject it. There is also a user-facing version of this problem: when someone saves an image from your site and gets a .webp their software cannot open, that is a small failure you caused. Convert for the web, where WebP is well supported, and keep PNG for anything you hand to a person or a system you do not control.
PNG is the screenshot format, and screenshots capture more than you aimed at
It matters what people actually have in PNG form, and overwhelmingly the answer is screenshots — because that is what every operating system produces when you press the capture key. A screenshot is a picture of your screen at one moment, and it is very rarely just the thing you meant to photograph. Around the edges sit your other browser tabs and their titles, a notification banner that arrived at the wrong second, the file path in a window title, a customer name in a support tool, an access token sitting in a URL bar, the beginning of a private message. People send these to hosted converters constantly, usually to save a few kilobytes on an image nobody will measure, and the file spends its time on a third-party disk in a form anyone with access can simply look at. Here the decode and the encode both run in the page, so nothing is transmitted and there is nothing to review afterwards — you can watch the network panel stay empty while a folder of captures converts.
How it compares
| Feature | This tool | Typical online converters |
|---|---|---|
| Images uploaded to a server | Never — converted in your browser | Usually uploaded |
| Choose lossless or lossy | Explicit choice | Often assumed |
| Keeps transparency | In both modes | Varies |
| Warns about the size limit | Before encoding | Fails silently |
| Image-count limit | Unlimited | Often capped on free tier |
| Price | Free | Free / paid tiers |
Features
Both WebP codecs
Lossless and lossy are offered as an explicit choice rather than one being silently assumed.
Alpha preserved in either mode
Transparency survives whichever codec you pick, which is the main thing WebP added over JPEG.
Adjustable quality
A visible slider in lossy mode, with a default that suits photographs rather than line art.
Oversize detection
Images beyond the format maximum are reported clearly instead of producing a failed or truncated file.
Batch conversion
Add a folder of PNGs and convert them in one pass without an upload queue.
No installation
Nothing to download or install — it runs on the web page.
Arabic and RTL friendly
Full interface in eight languages, including right-to-left Arabic.
Secure by default
Served over HTTPS, with no file tracking and no third-party upload.
Who uses it
Web developers
Replacing PNG assets with lossless WebP for the same pixels at a smaller size.
Online shops
Getting a cut-out product photo small without giving up its transparent background.
Performance engineers
Cutting image weight on pages where PNG graphics dominate the payload.
Anyone with a folder of captures
Shrinking screenshots for a wiki or an issue tracker without uploading them anywhere.
Frequently Asked Questions
WebP produces much smaller files than PNG at the same visual quality, so pages load faster and use less bandwidth. It also keeps transparency, making it a modern drop-in replacement for PNG on the web.
Yes. WebP fully supports an alpha channel, so transparent areas in your PNG stay transparent after conversion — unlike converting to JPG, which fills them with white.
Yes, you can adjust the quality slider from 1 to 100. Lower values produce smaller files; a value around 80 is a good balance of size and quality for most images.
No. The conversion runs entirely in your browser using the Canvas API. Your images are never uploaded, stored, or shared.