HEIF is the container HEIC lives in, read here and not written. PDF is a frozen page layout with no heading structure a machine can rely on. ImageMagick sits between the two, and this page says exactly what happens to a HEIF file on the way to becoming a PDF one.
What runs when a HEIF file becomes PDF
ImageMagick 6.9.12, on a machine we rent and watch. Your HEIF file is uploaded once, ImageMagick runs once, the PDF comes back, and neither file is kept. HEIF to PDF is one of the 3649 pairs that engine was probed on with a real file, which is why it has a page here and why the pairs the probe could not prove do not.
What survives from the HEIF into the PDF
The pixel dimensions of your HEIF file. The PDF comes out the size the HEIF went in, because nothing on this path resizes anything.
What HEIF to PDF costs you
Transparency. PDF has no alpha channel, so the engine composites your HEIF image onto white before encoding. Without that step ImageMagick lays black underneath, and a transparent HEIF logo comes back as a black rectangle.
The chance of getting text out. The PDF you receive is one page with your HEIF picture painted on it. Words inside the HEIF stay pixels, and nothing reading that PDF will find them.
Where HEIF and PDF files come from
HEIF. The container standard; HEIC is the name it goes by when the picture inside is HEVC. Read here and not written, because the write alias is not wired on the engine and pretending otherwise would hand you a file under the wrong name.
If a model is going to read the PDF
Worth knowing before the PDF goes anywhere near an assistant: this is the wrong direction for that. A PDF is a set of positioned glyphs, and a model has to reconstruct the reading order before it can begin. If a machine rather than a person is going to read this HEIF file, convert it to Markdown instead and skip the reconstruction entirely.
HEIF to PDF, measured rather than promised
Running HEIF to PDF against the real engine with a real file, ImageMagick wrote 94,782 bytes of PDF in under a tenth of a second, machine otherwise idle. That is one HEIF file on one day and not an average, which is why the number is given together with the file that produced it.
The HEIF to PDF verdict was reached by a format signature, meaning at least four bytes unique to the format were found at the right offset. Which check was used matters, because they do not all prove the same thing, and a status code of 200 proves nothing whatsoever about whether the PDF file has anything inside it.
The same HEIF file, sent somewhere else
Other outputs the probe measured out of a HEIF file, so the cost of choosing PDF can be read against something. Sizes do not compare across engines, because each family was probed with its own HEIF witness file.
HEIF to JPG: 1,666 bytes in under a tenth of a second, verified by a format signature.
HEIF to PNG: 1,403 bytes in under a tenth of a second, verified by a format signature.
HEIF to WEBP: 416 bytes in under a tenth of a second, verified by a format signature.
HEIF to GIF: 2,918 bytes in 0.1 seconds, verified by a format signature.
HEIF to TIFF: 90,264 bytes in under a tenth of a second, verified by a format signature.
Other ways into PDF, and what they measured
Among the published routes into PDF, HEIF is the seventh largest output of the 26 measured. The witness files differ, so this ranks the probe run and not your document.
ICO to PDF: 95,344 bytes in under a tenth of a second.
DOCX to PDF: 11,917 bytes in 1.2 seconds.
DOC to PDF: 11,917 bytes in 1.1 seconds.
XLSX to PDF: 18,965 bytes in 1.1 seconds.
XLS to PDF: 18,519 bytes in 1.0 seconds.
What we will not pretend about HEIF to PDF
A HEIF file over 25 MB is refused before the upload finishes rather than after it, so you do not wait for a rejection.
A HEIF to PDF run that passes 30 seconds is killed, and the ImageMagick process is killed with it. A run left behind would sit on one of the machine's two cores until somebody noticed.
No text is read out of the HEIF anywhere on this path. Converting a picture to PDF never turns it into words, whatever the picture happens to contain.
ImageMagick was not saturated at sixteen simultaneous conversions: it held 47.5 a second while latency moved from 0.22 s to 0.34 s, and the service memory did not move off 51 MB. That is the measured headroom behind HEIF to PDF, not a marketing number.
One HEIF file at a time, chosen in the browser. There is nothing else to set up and nothing else on offer.
HEIF to PDF: what people ask
What actually converts my HEIF file to PDF?
ImageMagick does it, 6.9.12, on a machine we rent and watch. Not a browser trick and not somebody else service: the HEIF file is uploaded once, ImageMagick runs once, the PDF comes back, and neither file is kept afterwards.
How long does HEIF to PDF take?
On the file the probe used, ImageMagick took under a tenth of a second and wrote 94,782 bytes of PDF. That is one real measurement on one real HEIF file, not an average and not a promise about yours: a larger HEIF takes longer, and past 30 seconds the run is stopped.
What do I lose going from HEIF to PDF?
The one to know about first: Transparency. PDF has no alpha channel, so the engine composites your HEIF image onto white before encoding. Without that step ImageMagick lays black underneath, and a transparent HEIF logo comes back as a black rectangle.
Can I put several HEIF files into one PDF?
No. One HEIF file goes in and one PDF comes out, with that picture on it. Nothing here merges files, orders them or numbers pages: it is one upload, one conversion, one download, and that is the whole of what this page does.
Is HEIF to PDF free?
There is a free allowance every month, and one HEIF to PDF conversion costs half a credit against it. When the allowance runs out the tool says so and stops, rather than quietly handing you a worse PDF.