What is HEIC? Why iPhones Use HEIC Instead of JPEG

What is HEIC?

HEIC stands for High Efficiency Image Container. It is the file format Apple uses to store photos taken on iPhone and iPad devices running iOS 11 or later. When you take a photo on an iPhone 7 or newer, the camera system saves it as a .heic file by default.

The name can be confusing because HEIC is actually a container format — a wrapper that holds one or more compressed images, along with metadata like GPS location, camera settings, and capture date. The image data inside the container is compressed using the HEVC (High Efficiency Video Coding) codec, also known as H.265.

HEIC is Apple's implementation of a broader international standard called HEIF (High Efficiency Image File Format). Other companies and devices can also use HEIF containers, potentially with different compression codecs, but Apple's specific use of HEVC compression in .heic files is what you'll encounter in the wild when working with iPhone photos.

HEIF, HEVC, and the Standards Behind It

HEIF was developed by the MPEG group (Moving Picture Experts Group) — the same organisation behind MP3, MP4, MPEG-2, and HEVC. The format was formally standardised as ISO/IEC 23008-12 in 2015. You can read more about the broader HEIF standard on Wikipedia's HEIF article.

HEVC (H.265) is the successor to H.264, the video compression standard that became ubiquitous in the 2000s. HEVC achieves approximately twice the data compression at the same visual quality level as H.264 — a major engineering achievement that makes it well-suited to high-resolution photography.

The choice to use HEVC for image compression rather than video is unconventional but technically sound. HEVC's inter-prediction and transform algorithms work just as effectively on still images as they do on video frames, and Apple's hardware HEVC encoders in iPhone chipsets meant there was no performance penalty for using it.

What HEIC Can Store

One of HEIC's significant advantages over JPEG is that a single .heic file can contain much more than one image:

• Image sequences — iPhone Live Photos store the still image and the short video clip in a single HEIC file
• Depth maps — Portrait mode photos store depth information alongside the main image, enabling computational bokeh effects
• HDR images — HEIC supports wide colour gamut (Display P3) and HDR image data
• Transparency — unlike JPEG, HEIC supports alpha channel transparency
• Full metadata — EXIF, XMP, and IPTC metadata are all supported

Why Apple Switched from JPEG to HEIC

Apple announced the switch to HEIC/HEIF as the default camera format at WWDC 2017 alongside iOS 11. The primary driver was straightforward: storage space.

iPhone cameras had been steadily increasing in resolution — from 8MP to 12MP, with larger per-pixel sensor sizes and higher-quality optics generating larger files. At the same time, iPhone storage sizes were not increasing proportionally in the entry-level tier. Apple needed a way to store more photos in the same space.

HEIC delivers approximately 40–50% smaller file sizes compared to JPEG at equivalent perceptual quality. For a user with 5,000 photos on their phone, this could mean the difference between running out of storage and having room for several years more shooting. On a 128GB iPhone, switching from JPEG to HEIC effectively provides the equivalent of an extra ~20GB of photo storage capacity.

Additional Technical Benefits

Beyond file size, HEIC offers Apple other technical advantages:

• Better colour depth — HEIC supports 10-bit and 12-bit colour depth versus JPEG's 8-bit, preserving more tonal gradations in low-light and high-dynamic-range scenes
• Native HDR support — HEIC images taken on HDR-capable iPhones store true HDR image data that displays correctly on HDR screens
• Better compression for smooth gradients — JPEG's DCT-based compression creates visible artefacts (banding) on smooth colour gradients like sky, which HEVC's more sophisticated prediction handles more cleanly
• Multi-image support — storing Live Photos, burst shots, and depth data in a single file simplifies the file management model

HEIC Compatibility: Where It Works and Where It Doesn't

The main practical problem with HEIC is compatibility. JPEG has been the universal standard for 30+ years and is supported by literally every device, operating system, browser, and application in existence. HEIC was new in 2017 and took years to gain meaningful support outside Apple's ecosystem.

Where HEIC works natively:

• All Apple devices (iPhone, iPad, Mac) running iOS 11 / macOS High Sierra or later
• Windows 10 and 11 — with the HEVC Video Extensions codec installed
• Modern versions of Android (varies by manufacturer)
• Google Photos (converts on upload for sharing)
• Most modern web browsers when viewing inline (via OS decoding)

Where HEIC commonly fails:

• Older Windows versions without HEVC codec installed
• Most image editing software that hasn't been updated recently
• Many website upload forms (particularly for profile photos, e-commerce, etc.)
• Email attachments viewed on non-Apple clients
• Social media platforms (most convert to JPG automatically on upload, sometimes reducing quality)

How to Open or Convert HEIC Files

The simplest solution for cross-platform compatibility is to convert HEIC files to JPG. This produces a universally compatible file that works everywhere JPEG works — which is essentially everywhere.

You have two main options for converting HEIC files:

Prevent HEIC at Source on iPhone

You can change your iPhone to save photos as JPEG instead of HEIC: go to Settings > Camera > Formats and select Most Compatible. This trades storage efficiency for compatibility. Photos will be saved as JPEG and videos as H.264 going forward.

A middle ground Apple also offers: keep shooting in HEIC on-device, but automatically convert to JPEG when transferring to a non-Apple device. Under Settings > Photos, the option Transfer to Mac or PC: Automatic converts files to JPEG during transfer via USB.

Convert Existing HEIC Files Online

For HEIC files you already have, an online converter is the fastest option. ToolMasta's HEIC to JPG converter converts HEIC files to JPG in seconds, directly in your browser, with no software installation required. The converted files are downloaded at full quality with no watermarks.

For a detailed walkthrough of the conversion process and tips for batch conversion, see our complete guide: How to Convert HEIC to JPG Online for Free. And if you want a deep comparison of quality and file size between the two formats, read our HEIC vs JPEG comparison.