Convert HEIC to PDF

Why do HEIC photos need converting?

Most upload forms, Windows apps and printers can't read HEIC, while every one of them accepts PDF. iPhones save photos as HEIC to save storage, which works well until a photo has to be attached to a job application, a school portal or a bank's document upload that only takes PDF or JPG.

Converting HEIC to PDF solves the compatibility problem and lets several pictures, such as both sides of an ID card or every page of a signed form, travel as a single document in a fixed order. The original HEIC files are left untouched, so the full-quality originals stay in the photo library.

What exactly is HEIC, and how does it differ from JPG?

HEIC is Apple's file extension for HEIF, a container standardised by MPEG in 2015 that stores images compressed with the HEVC (H.265) video codec. It reaches similar visual quality to JPG at about half the file size and supports 10-bit colour, depth maps and image sequences.

The drawback is support. HEVC is patent-encumbered, so browsers other than Safari do not decode HEIC natively, and Windows needs paid or optional extensions. JPG dates from 1992 and opens everywhere. A PDF built from JPG data is therefore the most portable way to hand an iPhone photo to someone else.

How does the in-browser HEIC decoder work?

The page loads a self-hosted JavaScript build of the libheif decoder, about 3 MB, and runs it locally with no network requests. Each photo is unpacked to full-resolution pixels, turned upright, encoded as a high-quality JPG and placed on its own page. Where the browser can already display HEIC, as Safari does, that native decoder serves as a fallback.

Because decoding is demanding, photos are handled one at a time with a progress count, so even a phone can convert a batch without crashing the tab. Live Photos contribute their still image; the motion part is ignored. Image sequences and burst files contribute their primary image only.

How do you get good results from photographed documents?

Use A4 or US Letter pages with a small margin, put the pages in reading order, and compress the result if it is too big to send. Photos of paper need slightly different handling than photos of people or places, and a few quick checks before pressing Create PDF avoid a second attempt:

• Choose A4 or US Letter with a small margin so the PDF prints at a normal size.
• Rotate pages in the list if a shot was taken in the wrong orientation.
• Compress PDF afterwards if the file is too large for an email or upload limit.
• Put the front of an ID card before the back, and check the page count before sending.
• Remove blurry duplicates from a burst so the PDF holds only the sharpest shot.
• Run OCR PDF to make the text in the photos searchable.

What are the limits of HEIC to PDF?

Each photo can be up to 50 MB, and photos above about 16 megapixels are scaled down to that size. Any current version of Chrome, Edge, Firefox or Safari can run the decoder. A 48-megapixel HEIC capture from a recent iPhone is therefore reduced, while standard 12-megapixel and 24-megapixel shots pass through at full resolution.

The resulting PDF is usually two to three times larger than the HEIC files, because JPG compression is less efficient than HEVC. That is the price of a file everyone can open. For email attachments with a 10 or 25 MB cap, run the finished file through Compress PDF. On an iPhone itself, the Files app can also create a PDF: select photos, tap More, then Create PDF.