If you have ever tried to email a photo from your iPhone and the recipient says they cannot open it, HEIC is probably the culprit. HEIC (High Efficiency Image Container) is Apple's default photo format since iOS 11. It produces files roughly half the size of JPEG at the same quality, which is great for storage. It is less great for compatibility.
Windows did not natively support HEIC until Windows 10 version 1809. Many web applications, email clients, and document management systems still do not accept it. And when you need to submit photos as part of a PDF document -- insurance claims, application forms, portfolios -- HEIC to PDF conversion is a common need.
Why HEIC exists
HEIC is based on the HEIF (High Efficiency Image Format) standard, which uses the same compression technology as H.265/HEVC video. The key advantages:
- 50% smaller files than JPEG at equivalent quality
- 16-bit color depth versus JPEG's 8-bit, preserving more color information
- Support for transparency (alpha channel), which JPEG lacks
- Multiple images in one file, enabling burst photos and live photos
- Non-destructive editing metadata, preserving the original alongside edits
The compression efficiency is genuine. An iPhone photo that would be 3.5 MB as JPEG is typically 1.5-2 MB as HEIC. With 128 GB of iPhone storage and tens of thousands of photos, this difference is significant.
The conversion challenge
Converting HEIC to PDF is a two-step process: decode the HEIC image, then encode it into a PDF document. The first step requires an HEVC decoder, which is not universally available due to patent licensing issues. HEVC is covered by multiple patent pools, and software that decodes it may need to pay royalties.
This is why many free tools and open-source projects have inconsistent HEIC support. The patent situation makes it legally complicated to distribute HEVC decoders in some contexts.
On macOS, HEIC conversion is trivial because the operating system includes native HEVC support:
# Convert HEIC to JPEG on macOS
sips -s format jpeg input.heic --out output.jpg
# Convert HEIC to PDF using Preview (via command line)
sips -s format pdf input.heic --out output.pdf
On other platforms, tools like ImageMagick (with the libheif plugin), FFmpeg, or dedicated conversion utilities handle it.
Batch conversion
When you need to convert dozens of photos -- common for insurance documentation, real estate listings, or portfolio compilation -- batch processing matters:
# macOS batch conversion
for f in *.heic; do
sips -s format jpeg "$f" --out "${f%.heic}.jpg"
done
Building a multi-page PDF
Often the goal is not individual image files but a single PDF containing multiple photos. This is where the workflow gets more complex:
# Using ImageMagick to create a multi-page PDF from HEIC files
convert *.heic output.pdf
# With quality control
convert -quality 85 -density 150 *.heic combined.pdf
Quality and density settings control the trade-off between file size and visual quality. For documents that will be printed, 200-300 DPI is appropriate. For screen-only viewing, 72-150 DPI keeps file sizes reasonable.
Browser-based HEIC handling
Modern browsers are gaining HEIC support, but it is inconsistent. Safari on macOS supports it natively. Chrome added support in version 85 but only on platforms with OS-level HEVC support. Firefox support varies by platform.
For web applications that need to handle user-uploaded HEIC files, the heic2any JavaScript library provides client-side conversion using WebAssembly, avoiding the need for server-side processing.
I built a HEIC-to-PDF converter at zovo.one/free-tools/heic-to-pdf that runs entirely in the browser. Drop your HEIC files, arrange the page order, and export a PDF. No upload to any server, no software installation, and no file size limits beyond your browser's memory. Particularly useful when you need to quickly compile iPhone photos into a document for submission.
I'm Michael Lip. I build free developer tools at zovo.one. 500+ tools, all private, all free.
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