WebP to AVIF Converter

What the upgrade actually buys you

AVIF uses AV1 coding, which is a more efficient compressor than the one in WebP. For photographs, that typically means 20 to 50 percent smaller files at a quality you cannot tell apart, which directly affects how fast a page loads on a phone. The gain is not uniform: it is largest for photographs with lots of detail, and modest for flat graphics where both formats already compress well.

NoteThese are indicative figures for the same perceived quality. Exact sizes depend on the encoder, the quality setting, and the image itself.

Converting WebP costs you a generation of quality

This is the part most guides skip. Your WebP is already lossy, so the pixels it holds are a reconstruction rather than the original. Re-encoding to AVIF reconstructs again from that reconstruction, and the difference accumulates. In practice one conversion is fine for web delivery. Repeatedly converting back and forth between WebP and AVIF is how an image degrades into mush, so keep the highest quality source you have and convert from it once.

• One conversion between modern formats is acceptable for web use.
• Keep your original file. Converting from the best source, not from a previous output, preserves more detail.
• Never round trip: AVIF to WebP to AVIF loses a little more each time.
• Do not use lossy conversion as an archival step. Keep a lossless master for anything you need to keep.

Where AVIF still needs a fallback

AVIF is supported across all current major browsers, which is why it is now a reasonable default rather than an experiment. Older browsers, some in-app webviews, and older operating systems do not support it, and a broken image on a business page costs more than the bytes you saved. The standard approach is to serve AVIF and fall back to WebP, which means keeping both files rather than replacing one with the other. If you cannot serve both, WebP is the safer single choice.

• Serve AVIF with a WebP fallback using a picture element or an HTTP content negotiation header.
• If you can only upload one file, choose WebP for the widest compatibility.
• Check your own analytics for the share of visitors on very old browsers before deciding.
• Keep the WebP files you already have rather than deleting them after converting.

MDN: image file type and format guide