What is a HEIC file?
HEIC (High Efficiency Image Container) is the photo format Apple adopted in iOS 11 in 2017. It is built on HEIF, an MPEG standard, and stores images compressed with HEVC (H.265), the same codec used for 4K video. The practical benefit is size: a 12-megapixel iPhone photo is around 1.5–3 MB as HEIC, compared with 3–6 MB as JPG at similar quality. HEIC can also hold 10-bit colour, depth maps for Portrait mode, and multiple images in one file.
The problem is compatibility. Windows needs an extra codec from the Microsoft Store before it can open HEIC, many web forms and online shops reject it, older versions of Android and most photo printers cannot read it, and a lot of desktop software simply shows an error. JPG, by contrast, opens everywhere. Converting is the simplest fix when you need to send photos to someone, upload them to a website, or edit them in an older program.
How this converter works
Most “free HEIC converters” upload your photos to a server, convert them there and send them back. That costs them bandwidth, which is why they limit you to a handful of files per day, and it means copies of your personal photos sit on someone else’s computer.
PixFoundry does the work locally. When you add your first file, the page loads libheif, the reference open-source HEIF decoder, compiled to WebAssembly. Each photo is decoded into raw pixels in a background Web Worker, then encoded to JPG with MozJPEG, an optimised JPEG encoder that produces smaller files than a standard encoder at the same quality. Because everything runs on your own processor, there is no daily limit and no waiting in a server queue. On a typical laptop a 12 MP photo converts in about one to two seconds.
Tips for the best result
- Quality 85–92 is the sweet spot. Below 80 you may see blockiness in skies and gradients; above 95 files grow quickly with little visible gain.
- Choose PNG only if you need lossless output. PNG files of photos are very large (often 15–25 MB for a 12 MP image) and are rarely worth it.
- Pick WebP for websites. WebP files are about 25–35% smaller than JPG at the same quality and are supported by all current browsers.
- Very large photos. 48 MP photos need a lot of memory once decoded. On phones with little RAM, convert them a few at a time instead of all at once.
Converting HEIC on other devices
On a Mac, the Preview app can export HEIC as JPG one file at a time, and the Photos app converts automatically when you drag pictures out. On Windows, the Photos app can open HEIC after you install the HEIF and HEVC extensions, but saving to JPG is still a manual, per-file step. This page works the same way on Windows, macOS, Linux, ChromeOS and Android in any modern browser, which makes it the quickest option for converting a large batch in one go.