Free tool · no signup · no upload
Bulk WebP & AVIF converter
Convert unlimited JPG and PNG images right in your browser. No credits, no file limits, no server — your images never leave your computer.
Drop images here or click to choose
JPG, PNG, HEIC, GIF, BMP — as many as you like
🔒 Conversion happens entirely on your device via WebAssembly — files are never uploaded, stored, or seen by anyone. HEIC decoding uses libheif (LGPL).
Why is this free and unlimited when others charge?
Every image-optimizer service that meters you with monthly credits does so because your images run through their servers, and servers cost money. This tool takes a different approach: the same open-source WebP and AVIF encoders that power professional tools are compiled to WebAssembly and run in your browser, on your computer. There's no server doing the work, so there's nothing to meter — and your files stay private as a side effect.
It's built by PrinterFlo, print shop management software — we make image-heavy websites for a living and got tired of credit systems too.
Frequently asked questions
Is this converter really unlimited and free?
Yes. Most image-optimizer services meter you with monthly credits because every image costs them server time. This tool converts images on YOUR computer, in your browser, using the same WebAssembly codecs Google built for Squoosh — so there is nothing for us to meter. Convert ten images or ten thousand.
Are my images uploaded to your server?
No. Nothing leaves your machine. The encoder runs locally in your browser via WebAssembly; we never transmit, store, or see your files. You can disconnect from the internet after the page loads and it still works.
WebP or AVIF — which should I choose?
AVIF compresses hardest — typically 30–50% smaller than JPEG at the same visual quality — and is supported by all modern browsers. WebP is a little larger but encodes much faster and has effectively universal support. For most websites: AVIF for photos where size matters most, WebP for everything else or when you're converting hundreds of files.
What quality setting should I use?
75–85 is the sweet spot for web images — visually indistinguishable from the original at a fraction of the size. Drop to 60–70 for large background/hero images where small artifacts are invisible, and use 90+ only when the image is the product (photography portfolios, print proofs).
Does it keep transparency?
Yes — both WebP and AVIF fully support alpha transparency, so transparent PNGs (logos, cutouts) convert with their transparency intact and usually shrink dramatically.
Why are WebP and AVIF better for my website?
Smaller images are the single biggest lever for page speed on most sites. WebP typically cuts JPEG/PNG weight by 25–35% and AVIF by 30–50% with no visible quality loss — which means faster loads, better Core Web Vitals, and better Google rankings.
Is there a WordPress plugin version?
It's on the way — the same unlimited in-browser engine as a free WordPress plugin that converts your whole media library and serves WebP/AVIF automatically. Until then, convert here and upload the results.
More free tools: printerflo.com/tools