Free batch image format converter — local, safe, no upload
Batch convert images to WebP, AVIF, JPG or PNG with a quality setting — for faster pages, HEIC photos that will not open, or forms that only accept JPG.
When you need a format change
Shrink web images by switching to WebP or AVIF; turn iPhone HEIC photos into files Windows and Android can open; satisfy an upload form that only accepts JPG or PNG — all in one run instead of one file at a time.
- Web or social images → WebP or AVIF: smaller files, supported everywhere modern
- Needs transparency → WebP or PNG: JPG has no alpha channel
- HEIC that other devices cannot open → JPG
- Still going back into a design tool → PNG: lossless, edit it as often as you like
Three steps for a whole batch
No sign-up, no queue: pick a format, hit run, done — all of it on your own device.
- Add images: click “Choose images” to multi-select, or drag the whole batch in. PNG / JPG / WebP / AVIF / HEIC all go in
- Choose the target format and quality — the quality slider hides itself for PNG, which is lossless
- Hit Convert, then download files one by one or take everything with “Download ZIP”; use Preview and drag the divider to compare
Conversion happens on your device too
Most online converters upload your files, convert them on a server and send them back. This page does not: decoding and encoding run in the tab you already have open.
- No upload queue: a few hundred images start processing the moment you hit Convert, not after a several-minute upload
- No free tier to hit: no limit on file count or size, no watermark, and no “results deleted after 24 hours” promise you have to take on faith
- Works offline: install it as a PWA and it keeps converting in aeroplane mode, because the compute is already on your machine
- The trade-offs, plainly: the codec engine loads once on first visit (your browser caches it afterwards), and phones have less memory to spare — keep huge batches for a desktop
Which format should you pick?
Short version: WebP or AVIF for small files, WebP or PNG when transparency matters, JPG when it has to open anywhere.
- WebP: typically 25–35% smaller than JPG at the same quality, supports transparency
- AVIF: another notch smaller, slower to encode, great for web images — browsers cannot encode AVIF themselves, so this site ships its own encoder (about 3.4MB): the first AVIF conversion downloads it once, then it stays cached
- JPG: the most compatible option — lossy, no transparency
- PNG: lossless with transparency, but large — icons, screenshots, files you will edit again
FAQ
Does converting lose quality? What quality setting should I use?
It depends on the target: JPG, WebP and AVIF re-encode lossily at the level you set (the 85% default is visually indistinguishable for most photos), while PNG is lossless and keeps every pixel. Use 90+ for archival copies, 80–85 for web images, below 60 for thumbnails. Each file is encoded once from the original you picked, so converting repeatedly never compounds the loss.
Why did my transparent PNG get a white background?
JPG has no alpha channel, so transparent areas have to be filled with a solid colour (we use white). Pick WebP or PNG as the target format to keep transparency.
How do I convert iPhone HEIC photos?
HEIC opens natively only on Apple devices. Add the photos, choose JPG as the target, and the output works on Windows, Android and every upload form. There is a ready-made “HEIC to JPG” preset page with the parameters already set.
How many files can I convert, and are they uploaded?
Nothing is uploaded: conversion runs in your browser via WebAssembly, the files never leave your device, and it keeps working offline. The only limit is memory — hundreds of ordinary photos are fine; a batch of enormous images (tens of megapixels each) is better split into runs.
Where do the converted files go?
Results appear in the workbench first (the preview lets you drag a divider to compare before and after), then you download them one by one or take the whole batch as a single ZIP. Nothing is stored on the page — reload and it is gone.
How is converting different from compressing?
Compressing targets a file size (say 20KB) and keeps the format; converting changes the format and re-encodes at the quality you choose. If you need both, wire Compress and Convert together in the workflow editor and run the whole batch in one pass.
Which apps can open WebP and AVIF files?
Every modern browser (Chrome, Edge, Firefox, Safari 14+) opens WebP directly, and AVIF works in recent Chrome, Firefox and Safari 16+. Messaging apps handle both, but some older Windows photo viewers and older Office versions cannot. Going somewhere uncertain? Choose JPG.
How much smaller do the converted files get?
At the same visual quality, PNG to WebP often halves the size, JPG to WebP typically saves another 25–35%, and AVIF goes one notch further at the cost of slower encoding. The other direction — WebP to PNG — usually makes files bigger, because PNG is lossless.
How many files can I convert, and is there a size limit per file?
There is no quota on file count or size: conversion runs locally and is limited only by your device memory. A few hundred ordinary photos per batch is fine; multi-megapixel giants are better split into runs — the page lowers its own concurrency when memory gets tight and marks any file that failed.