CONVERT
JPG → AVIF
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Convert JPEG to next-gen AVIF format for superior compression and HDR support.
JPEG was designed in 1992 for photographic content and bakes in a fundamental limitation: its DCT-based compression can only operate in the YCbCr color space with 8 bits per channel, and it has no alpha channel whatsoever. Every JPEG you publish discards transparency permanently and caps dynamic range at 256 levels per channel. AVIF, standardized by the Alliance for Open Media in 2019, uses the AV1 intra-frame codec wrapped in the ISOBMFF container and addresses both of those constraints directly. The practical upshot for web publishers is that the same photograph encoded at comparable subjective quality will typically occupy 40 to 60 percent fewer bytes in AVIF than in JPEG, which translates to measurable Core Web Vitals improvements on image-heavy pages. Converting an existing JPG library to AVIF is the dominant reason developers and content teams run this specific operation: the source images already exist, the originals are gone or impractical to re-export, and the goal is to reduce bandwidth without a visible quality regression.
JPEG Image
Source formatJPEG is the most widely used lossy image format on the web. It achieves small file sizes through adjustable compression, making it ideal for photographs and complex images where some quality loss is acceptable.
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 JPG to AVIF
Web pages that rely on JPEG assets are often the largest contributors to Largest Contentful Paint delays. AVIF's superior compression efficiency at equivalent SSIM scores means fewer bytes transferred per image, which directly benefits users on mobile networks. A secondary reason is future-proofing: Chrome 85+, Firefox 113+, and Safari 16+ all support AVIF natively, covering well over 90 percent of current browser traffic. Publishers converting large JPEG photo archives to AVIF can reduce image CDN storage and egress costs substantially without touching the visual output their audience sees.
HOW TO CONVERT
JPG → AVIF
Provide the JPG
Click or drag to upload. We accept a single JPG file per job, with an optional queue of additional images for batch mode.
Encode to AVIF
The conversion decodes the JPG, resolves the colour space to sRGB and writes the AVIF container around the pixel data.
Save the AVIF
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all AVIF outputs is produced instead.
Common Use Cases
Share across platforms
Send AVIF files to anyone without worrying about whether they have the right software for JPG.
Embed in documents
Drop AVIF output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
AVIF often produces smaller files than JPG for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
JPG vs AVIF — Strengths and limitations
What each format does best, and where it falls short.
JPG Strengths
- Excellent compression ratio for photographs (10:1 or better without visible quality loss).
- Universal support — every camera, phone, OS, and browser reads JPEG natively.
- Adjustable quality setting balances file size against visual fidelity.
- Embeds EXIF metadata (camera model, GPS, exposure) automatically.
- Progressive rendering for graceful loading over slow networks.
Limitations
- Lossy — every save degrades the image further (generation loss).
- No transparency channel (use PNG or WebP for that).
- Visible compression artifacts on text, sharp edges, and flat colors.
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.
JPG vs AVIF — Technical specifications
Side-by-side comparison of the technical details.
JPG
- MIME type
- image/jpeg
- Compression
- Lossy — Discrete Cosine Transform + quantization + Huffman coding
- Color depth
- 8 bits per channel (24-bit RGB or 8-bit grayscale)
- Max dimensions
- 65,535 × 65,535 pixels (baseline)
- Transparency
- Not supported
- Typical quality
- 75–90 for web, 95+ for print
AVIF
- MIME type
- image/avif
- Color depth
- Up to 12-bit per channel
- Max dimensions
- 65 536 × 65 536 px
- Container
- HEIF (ISOBMFF)
- Codec
- AV1 (intra-only)
- Color spaces
- sRGB, Display-P3, BT.2020, arbitrary ICC
| Specification | JPG | AVIF |
|---|---|---|
| MIME type | image/jpeg | image/avif |
| Compression | Lossy — Discrete Cosine Transform + quantization + Huffman coding | — |
| Color depth | 8 bits per channel (24-bit RGB or 8-bit grayscale) | Up to 12-bit per channel |
| Max dimensions | 65,535 × 65,535 pixels (baseline) | 65 536 × 65 536 px |
| Transparency | Not supported | — |
| Typical quality | 75–90 for web, 95+ for print | — |
| Container | — | HEIF (ISOBMFF) |
| Codec | — | AV1 (intra-only) |
| Color spaces | — | sRGB, Display-P3, BT.2020, arbitrary ICC |
JPG vs AVIF — Typical file sizes
Approximate file sizes for common scenarios.
JPG
- Phone photo (12 MP, quality 85) 2–5 MB
- Web thumbnail (400px) 20–60 KB
- Full-page magazine photo 500 KB – 2 MB
- Social-media square (1080×1080) 100–400 KB
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
A JPEG source already carries lossy compression artifacts: the 8x8 DCT block boundaries and chroma subsampling (most commonly 4:2:0 in web JPEGs) are baked into the pixel data before conversion begins. Re-encoding to AVIF does not remove those artifacts; it re-compresses pixels that already show them. At high AVIF quality settings (qp below 30 in libavif terms) the output will faithfully reproduce the JPEG artifacts. At lower quality settings, AVIF's own compression can sometimes mask JPEG blocking, but can also introduce its own ringing near sharp edges due to the AV1 transform. Bit depth: JPEG sources are 8-bit; AVIF supports 8, 10, and 12 bits per channel, but a JPEG-sourced AVIF encoded at 10-bit does not recover lost detail — it only up-samples values without new information. Alpha channel cannot be recovered from a JPEG source. Color profile metadata (embedded ICC profiles or sRGB tags) is preserved when the encoder reads and passes the JPEG color metadata to the AVIF container's colr box, which KaijuConverter handles automatically. EXIF metadata (camera model, GPS, date) is also carried over into the AVIF container's Exif item.
Tips for Best Results
- Set AVIF quality between 60 and 75 (on a 0-100 scale as used by most encoders) for photographic JPEGs — this range typically achieves 45-55% size reduction against a source JPEG at quality 85, while keeping SSIM above 0.95 and avoiding visible ringing.
- If your JPEG source uses 4:2:0 chroma subsampling (the default for web-optimized JPEGs), match that with 4:2:0 in the AVIF output rather than upgrading to 4:4:4 — upsampling chroma data that does not exist in the source adds bytes without visual benefit.
- Before bulk-converting a JPEG library, verify that your target deployment environment supports AVIF: serve AVIF with the correct MIME type image/avif and use an HTML picture element with a JPEG fallback for any audience on Safari 15 or older, which predates native AVIF decoding.
Frequently Asked Questions
It depends on the codecs involved. If both JPG 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 JPG exactly, but cannot recover detail that JPG had already compressed away.
Often yes, especially when AVIF is lossless. JPG 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.
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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.