Guide
HEIC to JPG: What It Costs You
Converting a HEIC is usually a compatibility decision rather than an improvement: you are trading a newer codec for one that everything on earth can open. This is what that trade actually costs, measured rather than assumed, and one thing it quietly gives you back.
Your file is often not HEIC already
This catches people out, so it is worth knowing before you convert anything. When you pick a photo from an iPhone's photo library and hand it to a website, iOS frequently converts it to JPEG on the way out of the picker. The file that reaches the browser is already a JPEG, whatever the Photos app shows you.
So "I need to convert my iPhone photos" is often a problem you do not have. You have it when you are moving files off the phone directly — AirDrop to a Mac, a cable copy, an iCloud download, a file manager — because those hand over the original.
The reliable test is not the file name and not the type your computer reports. Both lie: a HEIC frequently arrives with no MIME type at all, which is why the tool here accepts any image and then reads the file's first bytes to decide what it is really holding. A genuine HEIC begins with a box marked ftypheic and stores its picture as HEVC video frames — the same compression used for 4K video, applied to one still.
Converting roughly doubles the file
Compared at matched picture quality across eight photographs, JPEG needed on average 103% more bytes than HEIC for the same result — a spread from 62% to 168%. That is the honest cost of the conversion and it is not a rounding error: a 2 MB HEIC becomes a 4 MB JPEG that looks the same.
This is not JPEG being badly implemented. JPEG was standardised in 1992 and HEIC carries thirty years of codec research, so the gap is expected. It is the same reason your phone switched in the first place.
One caveat on that figure, because it is the kind of thing that makes published comparisons disagree: the test images were not iPhone originals, so both encoders started from the same decoded pixels. That measures the two codecs fairly against each other, which is the question here, but a real photo that has already been through HEIC once will behave slightly differently.
Rotation survives, which is not guaranteed
A photograph taken in portrait is often stored landscape with a tag saying "turn this ninety degrees to display it". Plenty of conversion tools read the pixels and drop the tag, and you get a sideways photo — a well-known way to lose an afternoon.
That was checked here rather than assumed. An image stored 120 by 80 with an orientation tag of 6 came back out of the conversion as 80 by 120, with the coloured edges where a correct rotation puts them. The browser applies the tag while decoding, so the rotation is baked into the pixels of the JPEG and no longer depends on anything downstream reading a tag.
What to do
Convert when something will not open the file — an older Windows machine without the HEVC codec, a print shop, an upload form that rejects the extension, software that has not been updated in a few years.
Do not convert as housekeeping. There is nothing wrong with a library of HEICs, and turning them into JPEGs doubles the space they take for no gain in quality.
Convert from the original, not from a copy that has already been through something else. And if the picture is going onto a web page rather than to a person, JPEG is not the destination you want anyway — WebP is about a third smaller again.
Common questions
Why did my photos get bigger after converting?
Because JPEG needs roughly twice the bytes of HEIC to hold the same picture — 103% more on average in the measurement here, with a range from 62% to 168%. Nothing has gone wrong; that is simply what the older codec costs. If the size matters more than compatibility, keep the HEIC.
Does converting reduce the quality?
Slightly, and unavoidably. The HEIC is already lossy, so decoding it and re-encoding as JPEG loses a little more on top — this is the same one-way street as any lossy-to-lossy conversion. At a sensible quality it is not visible, but it is real, so convert once from the original rather than repeatedly.
Image Converter →Will it strip the location data from my photos?
Yes. Tested with a real HEIC carrying camera make, model and GPS coordinates: the JPEG that came back had no EXIF block at all. If stripping metadata is what you actually want and you would rather not re-compress the picture to get it, use the EXIF remover instead — it removes the metadata without touching the pixels.
EXIF Remover →Why does my iPhone photo arrive as a JPEG already?
iOS often converts on the way out of the photo picker, so a website receives a JPEG even though Photos shows a HEIC. You get the real HEIC when you move the file off the phone directly instead — AirDrop, a cable, or an iCloud download. The tool handles both: it reads the file's own bytes rather than trusting the name or the type, and re-encodes whatever it actually finds.
Is my photo uploaded anywhere?
No. The HEIC decoder is a WebAssembly build that downloads to your browser the first time you press convert, and the decoding and re-encoding both happen on your device. The photo never leaves it, which for a file that came off a phone with coordinates in it is the point.