JPG to AVIF Converter

JPG to AVIF

AVIF's advantage over JPG is largest on exactly the images JPG handles worst: smooth gradients, skies, and low-light photography where JPG shows banding and blocking. Expect files half the size or better. Serve it through a element with a JPG fallback so older clients still get an image.

What Each Format Is For

JPG. JPG is lossy and has no transparency at all. Its discrete-cosine compression is built for photographs — smooth gradients, natural detail — and visibly degrades sharp edges and text into ringing artefacts. Every save re-encodes and loses a little more, so JPG is a delivery format, not a working one.

AVIF. AVIF, built on the AV1 video codec, compresses harder than WebP — often 20–30% smaller again at the same quality — with alpha, wide colour gamut and HDR. Encoding is slow and browser support, while now broad, is younger than WebP’s.

	JPG	AVIF
Compression	Lossy	Lossless available
Transparency	No	Yes

Transparency Survives

Both formats carry an alpha channel, so transparent regions convert without being flattened onto a background. That makes this a safe conversion for logos, icons and cut-out product photography.

The Conversion Runs in Your Browser

The file is decoded and re-encoded locally through a canvas. Nothing is uploaded, nothing is stored, and the conversion works with the network disconnected. For anything containing personal data — identity documents, medical images, private photographs — that is a meaningfully different risk profile from any server-side converter.

The practical limits are your device's memory on very large images, and the browser's own codec support: it can only encode formats it ships an encoder for, and the tool tells you when it cannot.

Quality Settings

AVIF can encode losslessly, so a conversion from a lossless source is exact — every pixel is preserved and re-encoding again later costs nothing.

One-Way Doors

Re-encoding never recovers information. If the target is lossy, keep the original: a AVIF converted back to JPG has the same artefacts as the AVIF, in a larger file. Treat converted output as a delivery copy and archive the source.

Sizing Before Compressing

Resizing beats compressing. Halving an image's dimensions removes 75% of its pixels, which no quality setting can match, and a 4000px photo displayed at 800px is wasting 96% of what it downloads.

Displayed at	Serve (1×)	Serve (2× for retina)
400px	400px	800px
800px	800px	1600px
1200px	1200px	2400px

Above 2× there is no visible benefit on any current display, and the file size keeps rising.

Quality Settings That Hold Up

Setting	Looks	Use for
95–100	Indistinguishable, large	Masters and print
80–90	Very good	Hero images, product photography
70–80	Good	Most web content
50–70	Visible artefacts on detail	Thumbnails
Below 50	Obvious	Nothing

Around 75–85 is where the curve bends: below it quality falls quickly, above it file size rises quickly for no visible gain.

Everything Runs Locally

Conversion and compression here use a canvas in your own tab. No file is uploaded, nothing is stored, and the work continues offline once the page has loaded. That is worth knowing for anything containing faces, documents or unreleased work — most online image tools upload by necessity, because they process server-side.

Getting the Rest of the Win

• Serve modern formats with a fallback. with AVIF, then WebP, then JPG.
• Always set width and height. Without them the page reflows on load, which

Google measures as Cumulative Layout Shift.

• Lazy-load below the fold — and never the hero, since loading="lazy" on it delays

the exact element Largest Contentful Paint measures.

• Strip metadata. EXIF can carry GPS coordinates and adds weight to every copy.