Convert BMP to AVIF

Convert BMP images to AVIF free, in your browser. No upload, no account, no watermark.

Runs in your browser. Nothing is uploaded.

Change the format. Drop an image, a PDF or a Word document.

Drop your files here images, PDFs or Word documents or paste with Ctrl+V
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    Your files are processed by your own browser and never sent to a server. Open your browser's network tab and convert one, there is no upload to see.

    How to convert BMP to AVIF

    1. Drop your BMP files onto the box above, or paste them with Ctrl+V.
    2. Pick a quality. Around 90% is indistinguishable from the original for most images.
    3. Your browser does the work on your own machine.
    4. Save each file from its tile, or take them all at once.

    What changes, and what does not

    Transparency is not gained

    AVIF can store transparency, but a BMP has none to give it. Converting cannot invent a transparent background; that needs an editor and a decision about which pixels should go.

    Detail is thrown away for the first time

    BMP keeps every pixel exactly. AVIF does not, and that is the point of it: the file gets far smaller because detail your eye is worst at noticing is discarded. Keep the original if you may need to edit it again.

    Colour

    BMP: 16.7 million, usually stored with no compression whatsoever. AVIF: millions, with 10 and 12 bit depth and wide colour where the source has it.

    BMP and AVIF side by side

    BMPAVIF
    Where it came from1987, as part of Windows2019, built on the AV1 video codec
    Throws detail away No, every pixel is kept Yes
    Transparency No Yes
    Animation No Yes
    Where it opensWindows software. Rare on the web, because the files are enormous.Every current browser. Outside the browser, support is still thin.
    Best atAlmost nothing today. It exists because old Windows tools still emit it.Photographs on a web page you want as small as they can honestly go

    How much smaller will the file be?

    Expect a large drop. A photograph saved as BMP carries every pixel exactly, and AVIF does not need to, so falls of eighty or ninety per cent are ordinary. A screenshot or a logo will fall much less, because BMP was already efficient at flat colour and hard edges, and may even grow.

    Can I convert it back afterwards?

    Not to the same file, no. Going to AVIF discards detail permanently, and converting the result back to BMP gives you a BMP of the damaged picture rather than the original. Keep the original if there is any chance you will need to edit it again.

    About BMP

    An uncompressed Windows format. Enormous files, no reason to keep them that way.

    About AVIF

    The smallest of the four, often half a JPG. We ship the encoder, so it costs a one-off download.

    Worth knowing: Needs a browser released in the last few years to decode.

    Will the quality change?

    AVIF is lossy, so the image is decoded and re-encoded and a little detail is dropped. At high quality this is invisible. Convert once from your original rather than repeatedly, because each pass compounds.

    Other conversions

    BMP also converts to JPG, PNG, WebP, PDF and Word.

    AVIF also comes from HEIC, PNG, JPG, WebP and GIF.

    Other tools

    Last updated August 2026

    Privacy

    Your files are never uploaded

    Every conversion happens inside your browser, on your own device. No server receives your file, so there is nothing for anyone to store, sell, lose in a breach, or be compelled to hand over. You can check: open your browser’s Network tab and convert something, there is no upload. The site also keeps working with your connection switched off.

    We collect nothing about you

    There are no accounts, no sign-up and no contact form. We do not ask for your name or your email address, and there is no database here holding anything about you.

    What is stored on your device

    Only preferences, such as the output format you last chose. That stays in your browser, is readable only by this site, and is removed if you clear site data.

    Hosting

    The site is served by Cloudflare Pages, which processes the technical information every browser sends with a request, an IP address and user agent, to serve pages and block abuse. That applies to page requests only. Your files are never part of a request.

    Analytics and advertising

    There is no analytics. The site carries advertising from Google AdSense to cover the cost of the domain. Google may set cookies or read a device identifier to choose and measure those ads, and you can review or change what it does at myadcenter.google.com and policies.google.com/technologies/ads. Advertising can never see your files, because your files never leave your device: the ad is a separate part of the page with no access to what you convert.

    Your choice about advertising

    If you are in the European Economic Area, the United Kingdom or Switzerland, you are asked before anything is stored on your device for advertising, and nothing is set until you answer. The message has three buttons and refusing is one of them, on the first screen, in one click, exactly like accepting. Refusing does not put the tools behind a wall and does not remove the advertising; it means the ads you see are chosen without a profile of you. You can change your answer whenever you like using the button at the end of this page, or by clearing this site’s data, which makes the message appear again. What Google does across all sites can be reviewed at myadcenter.google.com. None of this touches your files, which never leave your device to be seen by anyone, consenting or not.

    Getting in touch

    Write to leniv.tech@gmail.com. That address reaches one person. There is no support desk, no ticketing system and no newsletter to be added to, and your message is not stored anywhere other than that inbox.

    Terms

    Free to use

    For personal and commercial work alike, with no account and no watermark. Please do not try to disrupt the site or interfere with how it works for other people.

    Your files stay yours

    They never reach us, so we claim no rights over them and hold no copy of them.

    No warranty

    The tools are provided as they are. Conversion can fail on unusual or damaged files, and converting between formats can lose quality or detail, compressing a PDF, for instance, turns its text into part of an image. Keep your originals, and do not rely on this as the only copy of anything that matters. We are not liable for any loss arising from using the site.

    Changes

    These terms may change. The date above shows when they last did.