Convert HEIC to WebP

Key takeaways

• At the same quality setting (92%), the WebP was 2% to 20% smaller than the JPEG of the same picture.
• It also scored lower: SSIM 0.966 to 0.972, against 0.984 to 0.989 for the JPEG. The two scales are not the same, so compare results, not quality numbers.
• WebP is lossy here, so this is a second lossy step after HEIC. Use it for websites; for sharing with people, JPG opens everywhere.
• Your photos never leave the device, and several files can be converted at once.

Measured: HEIC to WebP

Measured in headless Chromium with the converter's own code: libheif 1.23 compiled to WebAssembly decodes the file, then the browser's canvas encoder saves it, as in the converter on this page. We had no phone files we could publish, so the HEIC files were made from three public domain NASA scans (a 3840 × 3877 photo, a 2122 × 2644 portrait and a 3827 × 1588 document scan) with libheif's HEVC encoder at three quality settings. A real iPhone file is encoded differently, so its size will differ. SSIM compares each result with an independent decode of the same HEIC file (1.0 would be identical).

A quality number means different things in different encoders, so matching 92% does not mean matching quality. The SSIM column shows what was actually kept.

Measured: how long decoding takes

Measured in headless Chromium with the converter's own code: libheif 1.23 compiled to WebAssembly decodes the file, then the browser's canvas encoder saves it, as in the converter on this page. We had no phone files we could publish, so the HEIC files were made from three public domain NASA scans (a 3840 × 3877 photo, a 2122 × 2644 portrait and a 3827 × 1588 document scan) with libheif's HEVC encoder at three quality settings. A real iPhone file is encoded differently, so its size will differ. SSIM compares each result with an independent decode of the same HEIC file (1.0 would be identical).

Decoding took 0.5 s to 1.8 s for 5.6 MP to 14.9 MP pictures. A phone photo of 12 megapixels sits inside that range. Your device will differ, and phones are usually slower than a desktop.

Measured: is the decoded picture right?

The decoder was checked against a second, independent decode of the same files (the Python package pillow-heif, which also uses libheif). Every pixel of every color channel was compared.

The largest single-pixel difference was 13 out of 255 and the average was under 0.4. Differences like this come from how two builds round the final conversion from the HEVC color format to RGB. Lossless PNG output of the 75 quality files scored SSIM 0.9999 or better against the reference.

HEIC vs WebP

What you get

A lossy WebP at 92% quality; transparency is kept. HEIC decoded in your browser and saved as WebP at 100%, 92% or 80% quality.

When WebP is the right choice

• You are putting photos on your own website and want smaller files.
• You need transparency and a smaller file than PNG.
• The destination states that it accepts WebP.

Free tools:HEIC to JPGJPG to WebPCompress an image to a target size

Make the iPhone save a compatible format

Apple's support page says iPhones from the iPhone 7 on, and several iPad models, can capture photos in HEIF, and that the more compatible older formats are available: in Settings, Camera, Formats, choose Most Compatible, and new photos are saved as JPEG.

The same page says that when you import photos from an iPhone or iPad over USB into Photos, Image Capture or a PC, the media might be converted to JPEG, and that Settings, Photos, Keep Originals turns that conversion off. It also says AirDrop, Messages or email can send a more compatible format when the receiving device does not support the newer one.

Questions people ask

More converters

• PNG to WebP
• JPG to WebP
• HEIC to JPG
• HEIC to JPEG
• HEIC to PNG
• AVIF to WebP
• SVG to WebP

Sources and how we checked

1. MDN: Media container formats
2. MDN: Web audio codec guide
3. MDN: Image file type and format guide
4. FFmpeg documentation: stream copy
5. Apple Support: Using HEIF or HEVC media on Apple devices (read 2026-10-09)
6. libheif (strukturag) README: HEIF and AVIF decoder and encoder (read 2026-10-09)
7. MDN: Image file type and format guide (read 2026-10-09)
8. Wikimedia Commons: NASA public domain photographs used to make the test files (read 2026-10-09)

Reviewed October 8, 2026. What the converter writes was measured with ffprobe on the same FFmpeg build your browser downloads; format descriptions follow MDN's media guides.