BMP to AVIF Converter
You have a bitmap and you want the leanest picture a modern website can serve. AVIF is a newer format that aims for very small files at good visual quality. This page converts BMP to AVIF inside your browser, provided that browser is able to write AVIF files.
How to convert BMP to AVIF
- Add your BMP files by dropping them, clicking the drop zone or pasting.
- The output format is already set to AVIF. Adjust quality or size if you need to.
- Press Convert and compare the original and new size for each file.
- Download each file or all of them as a ZIP.
When to convert, and when not to
- You run a site where page weight matters and visitors use up-to-date browsers.
- You are comparing formats and want to see what AVIF does to your particular picture.
- You can keep a JPG or WebP fallback for anyone whose software cannot open AVIF.
- Avoid it for files that must open everywhere, such as attachments or print jobs.
What changes
- The AVIF button is only enabled if your browser can encode the format. If it is greyed out, the tool is telling you honestly that it cannot make AVIF here.
- Compression is lossy, controlled by the quality slider.
- Encoding can take noticeably longer than for other formats, especially for large bitmaps, so convert big files one at a time.
- Transparency is supported by AVIF, and metadata from the bitmap is not carried over.
- Use the Resize option to bring oversized bitmaps down to a sensible pixel size first.
What AVIF offers a bitmap owner
Moving from BMP to AVIF is about as big a change in storage philosophy as you can make. The bitmap keeps every pixel unpacked, while AVIF applies modern video-style compression to store a picture in a fraction of the space for a given look. For photographs and gradients, the format is designed to hold up well even at low data rates.
No format is best for everything, so measure rather than assume. Convert one of your pictures to AVIF, then to WebP or JPG, and read the sizes in the queue.
If the AVIF button is disabled
Browsers differ in which formats they can write. When this page detects that yours cannot encode AVIF, it disables the option instead of quietly handing you a PNG with the wrong extension. In that case, try a current desktop version of a browser that supports AVIF output, or choose WebP, which is more widely supported for encoding.
Planning your fallback
A good publishing pattern is to serve AVIF to browsers that understand it and a JPG or WebP to the rest. Keep the original bitmap or a lossless PNG as your master file, because converting between lossy formats repeatedly degrades the image.
Before you commit to AVIF for a whole site, run a small experiment. Convert three or four representative pictures, read the sizes in the queue, and view each result at the dimensions visitors will see. If the saving over WebP is small for your kind of pictures, the extra encoding effort may not be worth it.
Also consider how you will deliver the files. A page that offers AVIF to capable browsers and a fallback to everyone else is more work to set up than a single JPG, so weigh that cost against the bandwidth you expect to save.
Privacy: your files stay on your device
- The tool decodes, resizes and encodes your pictures with your browser. The files are never sent to a server.
- To check it yourself: open the browser developer tools (F12), open the Network tab, convert a file, and look for any request that carries your image. You will see none.
Frequently asked questions
Why is AVIF greyed out for me?
Your browser cannot create AVIF files. Another current browser, or a different output such as WebP, will work.
Is AVIF smaller than WebP?
Often, but not always. Compare the actual sizes for your own pictures.
Will old software open the file?
Many older programs cannot read AVIF. Keep a JPG or PNG copy for those.
Why is conversion slow?
AVIF encoding is demanding, particularly for large images. Convert fewer files at once or reduce the size first.
Does it keep the bitmap's metadata?
No. Only the picture is written to the new file.