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Free browser-based tool

PNG to WebP Converter

Convert PNG images to WebP for smaller file sizes, or convert WebP back to PNG for maximum compatibility — entirely in your browser. No uploads, no server, 100% private.

Drop a PNG file here

or click to browse — max 20 MB

100% private. All conversion happens inside your browser using the Canvas API. Your image is never uploaded to any server.

How It Works

Step-by-step explanation

Select your image

Click the upload zone or drag and drop a PNG file (for PNG → WebP) or a WebP file (for WebP → PNG). The tool validates the file type and enforces a 20 MB size limit client-side before loading anything.

Preview and inspect

Your image is displayed immediately in a preview panel with a checkerboard background to reveal transparency. File name, format, size in KB/MB, and pixel dimensions are shown so you know exactly what you are converting.

Set quality (PNG → WebP only)

Use the quality slider to choose a value between 1 and 100. Higher values preserve more detail at the cost of larger file sizes. For most web images, 80–90 gives an excellent balance — typically 30–50% smaller than the original PNG with no visible quality loss at screen resolution.

Convert and download

Click Convert. The browser draws your image onto an HTML5 Canvas and re-encodes it to the target format using the browser's native codec — libwebp in Chromium, ffvpx in Firefox. The file downloads automatically. Nothing is ever sent to a server.

Formula

The math behind it

How the Canvas API converts images — zero dependencies:

// Load the selected image
              const image = new Image();
              image.src = URL.createObjectURL(file);

              image.onload = () => {
                // Create an off-screen canvas
                const canvas = document.createElement("canvas");
                canvas.width = image.naturalWidth;
                canvas.height = image.naturalHeight;

                // Draw the image
                const ctx = canvas.getContext("2d");
                ctx?.drawImage(image, 0, 0);

                // Export as WebP
                canvas.toBlob(
                  (blob) => download(blob),
                  "image/webp",
                  0.85 // Quality (0.0 – 1.0)
                );

                // Or export as PNG (always lossless)
                canvas.toBlob(
                  (blob) => download(blob),
                  "image/png"
                );
              };

The browser's native WebP encoder (libwebp in Chromium, ffvpx in Firefox) handles all compression. No third-party libraries are loaded — this is why the page stays fast and your image never leaves your device.

What is WebP?

WebP is a modern image format developed by Google, released publicly in 2010. It uses advanced compression algorithms — both lossy (similar to JPEG) and lossless (similar to PNG) — to produce files that are typically 25–35% smaller than equivalent PNGs and 25–34% smaller than JPEGs. WebP also natively supports an 8-bit alpha channel for transparency and animated frames, making it a direct drop-in replacement for PNG, JPEG, and GIF in web contexts. As of 2026, WebP is supported by over 96% of global browser installations.

What is PNG?

PNG (Portable Network Graphics) is a lossless raster image format standardised in 1996. It supports 24-bit colour depth and full 8-bit alpha transparency, making it the gold standard for logos, icons, UI elements, screenshots, and illustrations where every pixel must be preserved exactly. Because PNG compression is entirely lossless, file sizes are inherently larger than equivalent WebP or JPEG files. PNG has no support for animation (use APNG or WebP for that) and remains the preferred archival and editing format due to its zero-degradation re-save behaviour.

PNG vs. WebP — when to use each

Use WebP for web delivery: it gives you the same transparency as PNG but with 25–35% smaller files, which means faster pages and lower bandwidth bills. Use PNG when you need guaranteed universal compatibility — older design software, CMS platforms, email clients, print workflows, and stock photography sites still expect PNG or JPEG. The practical rule: convert to WebP for your website, keep PNG masters for editing and archiving.

Why convert PNG to WebP for your website?

Images are typically the largest assets on a web page. Serving WebP instead of PNG can cut image payload by 30–50%, directly improving Time to First Byte, First Contentful Paint, and Largest Contentful Paint — the Core Web Vitals metrics that Google uses as ranking signals. Google PageSpeed Insights explicitly flags PNG images as opportunities and recommends next-gen formats. Converting a 2.8 MB PNG hero image to WebP at quality 85 commonly produces a 1.1–1.4 MB file — saving over 1 MB per page load, per visitor.

Why convert WebP to PNG?

WebP is not accepted everywhere. Older versions of Adobe Photoshop (before 23.2), Microsoft Office, many email clients, and some CMS asset pipelines still require PNG or JPEG input. Converting WebP to PNG produces a universally compatible file you can open, edit, and upload to any platform. When the source WebP was losslessly encoded, the PNG output is pixel-perfect. When the source WebP used lossy compression, the PNG faithfully preserves that already-compressed data — it cannot undo prior quality loss, but it guarantees no further degradation.

Browser compatibility for WebP

WebP display is supported in Chrome 23+ (2012), Firefox 65+ (2019), Safari 14+ (2020), and Edge 18+ (2018). The Canvas API toBlob() method used for conversion is supported in all of those browsers too. Internet Explorer has no WebP support, but IE usage is below 0.3% globally as of 2026 and Microsoft officially retired it in 2022. If you need IE support, keep PNG — for everything else, WebP is safe.

Security and privacy

Most online image converters upload your file to a remote server, process it, and return the result — exposing your images to third-party infrastructure you have no visibility into. This tool is fundamentally different: conversion happens entirely inside your browser's JavaScript sandbox using the File API and Canvas API. The image bytes never leave your device. There is no server, no cloud storage, no logging, and no analytics on your images. You can verify this by opening browser DevTools → Network tab while converting — you will see zero image upload requests.

PNG vs. WebP — full format comparison

FeaturePNGWebP
CompressionLossless onlyLossless + Lossy
Transparency (alpha)✅ 8-bit alpha✅ 8-bit alpha
Animation❌ (APNG is separate)✅ Native
Typical file sizeLarger25–35% smaller
Browser supportUniversal96%+ globally
Software compatibilityUniversalLimited in older apps
Editing / re-savingZero degradationLossy mode degrades on re-save
Use caseEditing, archiving, printWeb delivery, performance

WebP vs. PNG file size — real-world comparison

The savings from converting PNG to WebP vary by image content, but the pattern is consistent across image types. Here are typical results at WebP quality 85:

Image typePNG sizeWebP size (q85)Saving
Hero / banner photo2.8 MB1.3 MB~54%
Product image (white bg)480 KB190 KB~60%
Logo with transparency120 KB48 KB~60%
Screenshot (UI)860 KB420 KB~51%
Illustration / flat art340 KB145 KB~57%

Results vary by image. Highly detailed photographs see the largest gains; flat-colour logos and icons typically save 50–65%.

Is WebP better for SEO?

Yes — indirectly but significantly. Google uses Core Web Vitals as a ranking factor, and image format is one of the most impactful levers for improving those scores:

  • Largest Contentful Paint (LCP): The LCP element is almost always an image. A 1.4 MB WebP loads and renders faster than a 2.8 MB PNG on the same connection, directly improving your LCP score.
  • Total Blocking Time (TBT): Lighter images reduce the network queue, freeing the main thread sooner and lowering TBT.
  • Bandwidth & crawl budget: Google's crawlers are rate-limited. Faster-loading pages are crawled more completely. Smaller images reduce the bytes Googlebot needs to fetch per page.
  • PageSpeed Insights score: Google explicitly flags 'Serve images in next-gen formats' as a high-impact opportunity. Switching to WebP directly removes this warning.

When NOT to use WebP

WebP is the right choice for web delivery in most situations, but there are specific cases where PNG remains the better option:

  • Image editing workflows: Always edit in PNG (or PSD/TIFF). If you save a WebP at quality 85, edit it, and save again at quality 85, you apply lossy compression twice. Each generation degrades quality. PNG is lossless — you can save a thousand times with zero degradation.
  • Print production: Print workflows (InDesign, Illustrator, press-ready PDFs) require formats like TIFF, EPS, or PNG. WebP is a screen-only format.
  • Legacy software compatibility: If your CMS, email platform, or client's toolchain does not support WebP, use PNG or JPEG. Forcing an unsupported format creates more problems than it solves.
  • Archiving original assets: Keep PNG masters of all important images. WebP is ideal for the output/delivery copy, not the canonical source of truth.

Image compression explained — lossy vs. lossless

Understanding the two types of compression helps you choose the right quality setting when converting PNG to WebP:

Lossless compression

Every original pixel is mathematically reconstructed on decode. File sizes are larger, but quality is 100% preserved regardless of how many times you re-save. PNG is always lossless. WebP lossless mode uses this approach too — select quality 100 in this tool for lossless-equivalent output.

Lossy compression

The encoder discards information the human eye is unlikely to notice — subtle colour gradients, fine texture noise, imperceptible edge details. The result is significantly smaller files. Quality settings (1–100) control how aggressively information is discarded. For web images, quality 80–90 is the sweet spot: typically 30–55% smaller with no visible difference on screen.

Transparency (alpha channel) is preserved in both PNG and WebP regardless of which compression mode you use. Transparent pixels do not degrade with lossy WebP compression.

FAQ

Frequently Asked Questions