When HEIC to JPG turns HEIC into JPG
Do this when an iPhone photo must be emailed, printed, or uploaded to a site that only accepts JPG.
What HEIC to JPG changes in the picture
The HEIC picture is decoded in the browser and saved as a JPG. The file leaves the Apple-only format.
JPG is lossy. Convert once, from the original HEIC, and keep the HEIC until you have checked the JPG. On iPhone you can also set Camera to Most Compatible so new shots are JPG.
Why HEIC to JPG is its own job
HEIC to JPG sits on this site because HEIC and JPG are not interchangeable, even when they look similar in a file list. Do this when an iPhone photo must be emailed, printed, or uploaded to a site that only accepts JPG. Windows PCs and a lot of upload forms still reject HEIC, which is why people convert it. Portals, printers, and chat apps that reject HEIC, WEBP, or AVIF are asking for JPG.
The HEIC picture is decoded in the browser and saved as a JPG. The file leaves the Apple-only format.
The HEIC file you already have
HEIC is the iPhone photo default. It stores more detail in less space than JPG. A browser cannot write a new HEIC. The useful direction is HEIC out to JPG or PDF.
Keep the HEIC on the phone until the JPG looks right.
What a JPG result is for
The download has to be JPG, because that is the format the next step named. Portals, printers, and chat apps that reject HEIC, WEBP, or AVIF are asking for JPG. It is small and universal for photographs.
Convert once from the best original. A second lossy save only throws away more.
How to tell that HEIC to JPG worked
HEIC to JPG is worth using only when JPG is what the next step actually named. Do this when an iPhone photo must be emailed, printed, or uploaded to a site that only accepts JPG. What you get from HEIC to JPG: The HEIC picture is decoded in the browser and saved as a JPG. The file leaves the Apple-only format. Before you trust it: JPG is lossy. Convert once, from the original HEIC, and keep the HEIC until you have checked the JPG. On iPhone you can also set Camera to Most Compatible so new shots are JPG. The file stays in your browser and is not uploaded. The limit is 100 MB. Keep the original until the download has been opened in the program that will use it. A second pass rarely helps. If the first JPG file is rejected, read the error from the program that rejected it. Another conversion of a bad result usually makes the file worse, not more compatible. When you are done, you should still have the HEIC original and one JPG download that you have opened. If those two are the same kind of failure, this was the wrong tool and the page above is the place that says so. Photos fail uploads for three separate reasons: the format name, the pixel size, and the kilobyte size. HEIC to JPG only does the HEIC to JPG step. If the form also prints a pixel size or a 20 KB or 50 KB cap, do that step with the matching tool, starting from the original each time. A second lossy save will not recover detail.
Here is the decision for HEIC to JPG. You start with HEIC and you stop when a real program accepts JPG. On the iPhone it is an efficient original. JPG is lossy. Saving it again softens fine detail. It cannot store transparency. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
JPG is lossy. Convert once, from the original HEIC, and keep the HEIC until you have checked the JPG. On iPhone you can also set Camera to Most Compatible so new shots are JPG.
A related step, if you still need one, is JPG to HEIC.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.