HEIC vs JPEG: what actually differs

Size: how much smaller HEIC is

Under the most commonly cited conditions — same resolution, comparable visual quality — a HEIC file is typically 50% to 60% the size of the JPG, in other words 40% to 50% smaller.

That gap comes from the codec. HEVC uses much larger transform blocks than JPEG (up to 64×64 versus 8×8), more refined intra-frame prediction, and better entropy coding. These techniques were designed for 4K video and work just as well on a single still frame.

The advantage is not constant — content matters a lot:

• Photos with smooth gradients (skies, skin tones) — the biggest win, often well under half the JPG size.
• Detail-heavy photos (foliage, fabric, dense text) — the gap narrows, sometimes to only 25% to 35%.
• Images that were already compressed — gains shrink, because the information was already discarded the first time round.

Quality: which looks better

At an equal file size, HEIC is clearly better — a direct consequence of coding efficiency. At an equal visual quality, the HEIC file is smaller. Those are two ways of stating the same fact.

JPEG's characteristic failures show up clearly at low quality: 8×8 block edges, ringing around sharp edges, and banding across smooth areas. HEIC, with bigger blocks and in-loop filtering, shows far less of this at the same compression ratio.

The reverse is also worth noting: JPEG has been stable for three decades, and decoder implementations differ very little, so what you see is essentially what everyone else sees. HEVC implementations vary slightly more, and in edge cases that can produce small differences between viewers.

On the specific question of how much quality a JPG conversion costs, we measured it on our own pipeline across quality settings — see the HEIC to JPG quality measurements.

Compatibility: this is where they diverge

This is the one dimension JPG wins outright, and by a wide margin.

JPEG dates from 1992 and is practically a synonym for the word image. Every operating system, every browser, every printer, and every upload field on the web accepts it without question. Nobody ever has to explain what a JPG is.

HEIC is the opposite story. Its core codec carries heavy patent licensing, so decoders cannot be bundled freely, and the container is far more complex than JPG. The result:

• Everything works inside Apple's ecosystem.
• Windows needs an extra extension.
• No mainstream browser can display it directly.
• Most online portals reject it on sight.

In other words, HEIC did not lose on technology. It lost on ecosystem.

Features HEIC has and JPG cannot

As a container, HEIF can carry considerably more:

• Multiple images in one file — a main image plus thumbnails and auxiliary images. Burst shots and Live Photos depend on this.
• Depth data — the distance map from Portrait mode is stored alongside, so depth of field can be re-adjusted later.
• HDR gain maps — letting a photo display higher dynamic range on capable screens.
• Lossless rotation — orientation can be recorded in metadata, so rotating requires no re-encoding and no quality loss.
• Alpha channel — the HEIF specification supports transparency, which JPG does not at all (that needs PNG or WebP).

Most of this is lost on conversion to JPG. A JPG is one flat image: no depth, no HDR gain, no transparency. That is why keeping the original HEIC before converting is worth doing.

Which to use, and when

In one line: HEIC is for keeping, JPG is for sending. They are not substitutes for each other — they are a division of labour.