How to Batch Convert Hundreds of HEIC Files at Once
My mum handed me a USB drive last Christmas with “a few photos” she wanted printed. It had 847 HEIC files on it. The print shop’s website wanted JPGs. I wasn’t about to convert them one at a time.
If you’re staring at a folder full of HEIC files and need them in literally any other format, here’s how to get it done without losing your mind.
The browser approach (what I actually use)
heic.site handles batch conversion. Select your HEIC files, drag them into the browser, and it chews through them one by one; when it finishes, “Download All as ZIP” hands you a single archive with the whole lot converted.
Worth knowing up front: the free tier converts three files per batch. There’s no cap on the number of batches. A big library is entirely doable for free, in chunks. Pro lifts that limit. Worth $5 a month if dragging a whole folder in one go appeals.
Two things I like about this:
Nothing leaves my computer. The conversion runs entirely in the browser using WebAssembly. When I’m converting personal photos — family stuff, medical records I photographed, whatever — I don’t want them sitting on some company’s server. Even temporarily.
No installs. I was on my mum’s ancient laptop when I needed to do this. Downloading and installing ImageMagick or some random converter app wasn’t an option. A browser tab worked.
If you’re on a Mac using Safari, it’s noticeably faster because Safari can decode HEIC natively. On Chrome or Firefox, the WebAssembly decoder is solid but slower. Expect a couple of seconds per photo on an average laptop.
Picking your settings
Format choice. JPEG for anything you’re going to print, email, or upload to a service. WebP if the files are going on a website (25-35% smaller than JPEG). PNG only if you specifically need lossless quality, and brace yourself for the file sizes.
Quality. 92 for JPEG. That’s the sweet spot where the file is noticeably smaller than HEIC but you can’t tell the difference visually. (There’s a full HEIC vs JPG quality breakdown if you want the numbers.) Going lower to 85 saves more space and still looks fine for most photos. I wouldn’t go below 80 unless you’re really tight on space and don’t care about close-up quality.
Batch size. Your browser has limited memory. This only matters once you’re on Pro and the per-batch cap is off. I’ve pushed through 200 files at a time on a newer laptop without issues, but on an older machine with 4 GB of RAM, 50-75 at a time avoids things getting sluggish.
Keeping things organised after
Once you’ve got your converted files, a few things that’ve saved me headaches:
Don’t delete the originals. HEIC files store 16-bit colour, and may carry depth maps or Live Photo data as well. The JPEGs are for sharing; the originals are your archive. Storage is cheap. If you’re on Windows and can’t even view them, here’s how to open HEIC files.
The converter keeps filenames. IMG_1234.heic becomes IMG_1234.jpg. Your existing folder structure and naming system carries over, so sorting and finding things later works the same way.
Date-based folders. If you’re converting years of photos, break them into batches by date or event. Converting everything into one flat folder makes for a bad time later when you’re looking for a specific photo.
When your computer can’t keep up
Conversion always runs on your own machine. There’s no server-side mode on any plan, which is the whole point of the tool, and it means a slow laptop stays a slow laptop whatever you pay me. Smaller batches are what actually help. The work happens one file at a time, so splitting 800 photos into runs of 50 keeps memory flat and finishes just as quickly overall. Leave the tab in the foreground while it’s going, because browsers throttle background tabs.
If you’re doing this often enough that the three-file limit is the annoying part, heic.site Pro takes it off and you can queue a whole folder, then collect one ZIP at the end. It’s still your CPU doing the work.
If you need the converted photos as PDFs instead, you can convert images to PDF the same way, right in the browser with nothing uploaded.