CONVERT
HEIF → AVIF
Fast, secure HEIF to AVIF conversion. No registration required.
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Situation. HEIF is the generic High Efficiency Image File container for HEVC and related codecs. Solution: a AVIF, produced below. Converting HEIF to AVIF swaps one image container for another without leaving the image family. The choice usually comes down to compatibility with the tool or platform that will consume the file next — some editors handle AVIF natively while HEIF still requires a plugin or extra step. KaijuConverter re-encodes in the browser session with ImageMagick, preserving resolution and colour profile, and leaves the source HEIF untouched. Worth knowing: HEIF is the generic High Efficiency Image File container for HEVC and related codecs. Meanwhile AVIF is the AV1-based next-gen image codec, extremely efficient with full HDR and alpha support.
HEIF Image
Source formatHEIF (High Efficiency Image File Format) is the container format behind HEIC. It supports advanced features like image sequences, depth maps, and HDR but has limited cross-platform support.
AVIF Image
Target formatAVIF is a next-generation image format based on the AV1 video codec. It offers significantly better compression than JPEG and WebP while maintaining excellent visual quality, including HDR and wide color gamut support.
Why convert HEIF to AVIF
Both HEIF and AVIF describe a grid of pixels — the difference lies in how that grid is compressed, whether transparency is supported, and which software opens it natively. Moving from HEIF to AVIF is worth it when the AVIF ecosystem is broader for your use case, or when AVIF compresses photographs more efficiently than HEIF.
HOW TO CONVERT
HEIF → AVIF
Drop the HEIF file
Drag and drop or click to upload your HEIF. The image is transferred securely over HTTPS and queued for conversion.
Re-encode with ImageMagick
ImageMagick decodes every pixel of the HEIF and writes a matching AVIF with sensible default quality settings.
Download the AVIF
The converted AVIF is ready to download as a single file; both files delete automatically within two hours.
Common Use Cases
Web publishing and CMSes
AVIF uploads cleanly to WordPress, Ghost, Webflow and most blogging platforms; many CMSes silently transcode or reject HEIF.
Email attachments
Email clients preview AVIF inline while HEIF may arrive as an unrecognised attachment on older Outlook or mobile apps.
Social media uploads
Platforms like Instagram, X and Facebook accept AVIF natively; HEIF is often rejected or silently converted with unpredictable results.
Design hand-off
Designers shipping assets to developers prefer AVIF for faster pipeline imports and consistent display across build tools.
HEIF vs AVIF — Strengths and limitations
What each format does best, and where it falls short.
HEIF Strengths
- ~50% smaller than JPEG at equivalent quality, with better detail retention.
- Container holds multi-image bursts, depth maps, and HDR data in one file.
- Supports 10 and 12-bit color, wide gamut, and HDR out of the box.
- Default iPhone camera format since 2017 — billions of files in existence.
Limitations
- HEVC codec inside .heic is patent-encumbered — licensing fees steered the web toward AVIF.
- Windows, Android, and most email clients needed plugins or recent updates to open HEIC.
- Encoding is CPU-intensive on older hardware.
AVIF Strengths
- Best-in-class compression efficiency — 30-50% smaller than JPEG for the same quality.
- Royalty-free and patent-unencumbered (unlike HEIC).
- Supports alpha transparency, HDR, wide gamut (BT.2020), and up to 12-bit color.
- Progressive decoding: a blurry preview appears while the file is still downloading.
- Supported in all major browsers since late 2022 — no polyfills needed.
Limitations
- Encoding is CPU-expensive — an AVIF export can take 10-30× longer than JPEG.
- Older software (pre-2022) cannot open AVIF without plugins.
- Email clients still largely ignore it — stick to JPEG for attachments.
HEIF vs AVIF — Technical specifications
Side-by-side comparison of the technical details.
| Specification | HEIF | AVIF |
|---|---|---|
| MIME types | image/heif, image/heic | — |
| Extensions | .heif, .heic, .heifs, .heics | — |
| Container | ISO Base Media File Format (ISOBMFF) | HEIF (ISOBMFF) |
| Codecs | HEVC (H.265), AV1, VVC (H.266) | — |
| Standard | ISO/IEC 23008-12 | — |
| MIME type | — | image/avif |
| Codec | — | AV1 (intra-only) |
| Max dimensions | — | 65 536 × 65 536 px |
| Color depth | — | Up to 12-bit per channel |
| Color spaces | — | sRGB, Display-P3, BT.2020, arbitrary ICC |
HEIF vs AVIF — Typical file sizes
Approximate file sizes for common scenarios.
HEIF
- iPhone photo (12 MP) 1-3 MB
- Portrait mode (with depth map) 2-4 MB
- Burst of 10 shots 5-15 MB
- 4K ProRAW-equivalent HEIF 10-30 MB
AVIF
- Thumbnail (400px) 10-30 KB
- Web photo (1920px) 80-300 KB
- 4K photo (3840px) 300 KB - 1.2 MB
- Lossless copy of 24MP photo 8-15 MB
Quality & Compatibility
If AVIF is a lossless format (PNG, TIFF, BMP) the output keeps every pixel of the decoded HEIF exactly. If AVIF is a lossy codec (JPEG, WebP, HEIC), the encoder re-compresses the image at the quality level you select — default 85 is transparent for photographs, quality 92+ for illustrations with hard edges.
Tips for Best Results
- Keep the original HEIF alongside the AVIF output — re-encoding already-lossy images accumulates detail loss on each round.
- If the AVIF will be uploaded to a CMS, check whether the platform has a max dimension and downscale once on export rather than letting the CMS resize automatically.
- For thumbnails and avatars, export the AVIF at exactly the display size; browsers will otherwise resample and the image may look soft.
Frequently Asked Questions
Frequently Asked Questions
It depends on the codecs involved. If both HEIF and AVIF are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If AVIF is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded HEIF exactly, but cannot recover detail that HEIF had already compressed away.
Often yes, especially when AVIF is lossless. HEIF tuned for efficient web delivery will usually produce smaller files than AVIF's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Related comparisons
See these formats side by side to understand which fits your use case best.
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.