Free, no account, no watermark. Your BMP files are turned into AVIF inside this browser tab — they are never uploaded to a server.
Nothing leaves your device
No account, no email
Free, and no watermark
Drop your files here
Tap to pick your photos
or
Choose files
Up to 30 files at a time · 60 MB per file
Higher quality means a larger file.
Advertisement
Ad slot — inactive until AdSense approval
Why convert BMP to AVIF?
The largest size reduction available for an old Windows bitmap. BMP stores pixels raw and AVIF is the most efficient format browsers understand, so a 25 MB scan can land in the low hundreds of kilobytes. Worth it when the destination is a web page; if the file is going into an editor instead, PNG is the safer target because far more software can open it.
AVIF is the pick when bandwidth matters most and your audience is on current browsers. A hero image can often be cut to a third of its JPEG size with no visible difference.
How to convert BMP to AVIF
Drop your BMP files into the box above, or click to pick them from your device.
Adjust the quality slider if you want a smaller file or a sharper result.
Hit convert. The work happens inside your browser, so it takes a second or two per image.
Download each AVIF file, or grab them all in one ZIP.
About the formats
BMP — Windows Bitmap
BMP stores pixels essentially raw, with little or no compression at all. That makes it trivially simple for software to read and absurdly large to keep around: a photo that would be 2 MB as JPG can comfortably run past 20 MB as BMP. It survives mostly inside Windows software, scanner drivers and older industrial tools.
Strengths
Completely lossless, with no compression to undo
A dead-simple format that even very old software can read
No patents and no licensing questions attached
Limitations
Wildly larger than any modern format, often by ten times or more
No meaningful compression whatsoever
Effectively unsupported outside the Windows world
AVIF — AV1 Image File Format
AVIF is the newest format here, built on the AV1 video codec. It beats WebP by another 20–30% on size, handles HDR and wide colour gamut, and supports transparency and animation. Encoding is slow and desktop support is still patchy, but for images delivered over the web it is the most efficient option browsers actually understand.
Strengths
The smallest files of any format with real browser support
HDR and 10-bit colour, so gradients do not band
Transparency and animation included
Limitations
Slow to encode compared with JPEG or WebP
Older browsers and most desktop applications cannot open it
Editing software support remains thin
Advertisement
Ad slot — inactive until AdSense approval
Frequently asked questions
Are my photos uploaded anywhere?
No. The conversion runs entirely in your browser using WebAssembly and the Canvas API. Your images are never sent over the network, never touch a server, and are dropped from memory as soon as you close the tab.
Will I lose quality?
AVIF is a lossy format, so some data is discarded. At the default quality of 85% the difference is invisible on screen for most photos. Raise the slider if you plan to print or edit the result.
Is there a limit or a cost?
It is free and there is no account. The only limits are practical: 30 files at a time and 60 MB per file, so that the tab does not run out of memory on a phone.
Can I convert several files at once?
Yes — drop in up to 30 files and they are processed one after another, then downloaded individually or as a single ZIP.
Does it work offline?
Once the page has loaded, yes. The converter itself needs no network connection, so you can drop the connection and keep converting.
Does it work on a phone?
Yes, on iOS and Android. Large batches are slower on a phone because the decoding happens on the device, so stick to smaller groups if things feel sluggish.