HEIC to JPG.

If you own an iPhone made after 2017, every photo you take is saved in HEIC format by default. HEIC — High Efficiency Image Container — is Apple's implementation of the HEIF standard developed by the Moving Picture Experts Group (MPEG). It uses the same HEVC (H.265) compression algorithm that powers 4K video streaming on Netflix, but applied to still images. The result is remarkable: a 12-megapixel iPhone photo in HEIC typically occupies 2–3 MB, while the equivalent JPEG would be 4–6 MB at the same visual quality.

The Compatibility Problem

Despite its technical superiority, HEIC's adoption outside Apple's ecosystem has been slow and frustrating. The core problem is patent licensing: HEVC (H.265) is covered by multiple patent pools requiring royalty payments, which has slowed adoption in open-source software and made some vendors hesitant to implement it. This creates a fragmented landscape:

HEIC vs JPEG: The Technical Comparison

JPEG was invented in 1992 and uses Discrete Cosine Transform (DCT) compression. It divides images into 8×8 pixel blocks and discards high-frequency detail according to the quality setting. It is fast to decode, universally supported, and well understood. Its main weakness is that at high compression ratios, the block boundaries become visible as "compression artefacts."

HEIC/HEVC uses a fundamentally different approach: variable block sizes (4×4 to 64×64), inter-prediction between image regions, and more sophisticated entropy coding. It avoids the blocking artefacts of JPEG and preserves fine detail better at the same file size. The trade-off is that decoding HEVC requires significantly more CPU/GPU compute power — which is why HEIC conversion is slower than JPEG processing.

For everyday photography, the practical differences are: at 90% quality, a HEIC and a JPG from the same photo look essentially identical on a standard display. The difference shows up at very high zoom levels or on professional print output. For social media sharing, email, and general use, JPG at 85–90% quality from a HEIC conversion is perfectly sufficient.

Choosing the Right Output Format

JPEG (JPG) is the right choice for 95% of use cases. It's universally compatible, produces small files (2–5 MB for a 12MP photo at 90% quality), and is accepted by every platform, app, email service, and website. Use JPEG for sharing, uploading, archiving for general use, and any situation where compatibility matters most.

PNG is the right choice when you need lossless quality — zero degradation from the original. The downside is file size: a 12MP HEIC photo converted to PNG can be 15–30 MB. Use PNG for professional photo editing workflows, screenshots, images with text or sharp graphic elements, or any case where you plan to edit the file further and want to preserve maximum quality.

WebP is Google's modern image format that offers better compression than JPEG (30% smaller at comparable quality) and is now supported by all modern browsers (Chrome, Firefox, Safari 14+, Edge). Use WebP if you're converting HEIC photos for use on websites, web apps, or platforms that support WebP — you get better quality at smaller file sizes than JPEG.

How heic2any Works in the Browser

HQCalc uses heic2any, an open-source JavaScript library by Alex Corvi, to perform HEIC conversion entirely in the browser. Under the hood, heic2any uses a WebAssembly (WASM) port of libheif — the reference C library for reading HEIF files. When you drop a HEIC file, the library decodes the HEVC bitstream in WASM, extracts the raw pixel data, and then re-encodes it to your chosen format using the browser's built-in Canvas API.

This approach is completely private by design — no bytes of your image data are ever transmitted to a server. The WASM module runs in your browser's sandboxed JavaScript environment. You could disconnect from the internet after the page loads and the converter would still work perfectly.