BMP to AVIF Converter

Convert BMP to AVIF Online

A BMP stores raw pixels with no compression — about three bytes for every pixel at 24-bit colour, which puts a 4000x3000 bitmap near 36 MB no matter what it depicts. AVIF, built on the AV1 codec's intra-frame coding, is the opposite: MDN puts lossy AVIF images at roughly 50% smaller than the equivalent JPEG, and JPEG is already an order of magnitude below an uncompressed bitmap. Upload your BMPs below to turn them into modern, web-ready AVIF files. Everything is uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

How to Convert BMP to AVIF

1. Upload Your BMP Files: Drag and drop your bitmaps onto the page or click "Add Files" to pick them. Several BMPs can be queued and converted in one batch with identical settings.
2. Set the Quality Preset: Under Image Compression, Quality Preset opens on Very High (Recommended) and runs from Highest down to Lowest. Highest and Very High are the right range for photographs; stepping down to High or Medium trades visible detail for a smaller file.
3. Or Aim at a Size Instead: Swap Image Compression to Specific file size to name an exact figure in Megabytes or Kilobytes — the percentage-based quality and size modes don't appear on this convert page. Under Image resolution, Keep original preserves the bitmap's pixel dimensions, and Preset Resolutions or Width x Height cap them.
4. Convert and Download: Click "Convert" and save your AVIF. No sign-up, no watermark, and nothing is shared or made public.

BMP Format at a Glance

AVIF Format at a Glance

Which Compression Control Should You Use?

The two modes under Image Compression are alternatives, not layers — you pick one and the encoder works to it. Quality Preset is the sane default because it maps to a perceptual target rather than a number: leave it on Very High (Recommended) and the output will look like the source at a fraction of the size. Specific file size inverts the problem — it lets you name the budget and accept whatever quality fits, which is what you want when a CMS or an email gateway imposes a hard cap. The finer percentage-based dials belong to the compressor pages rather than this convert page.

One thing this page deliberately does not offer is a lossless switch; that control exists only for WebP output. If your goal is a mathematically exact copy of the bitmap rather than a small one — an archival master, or an image you will re-edit repeatedly — convert BMP to PNG instead. PNG is lossless by design and still a fraction of the raw bitmap's size.

Frequently Asked Questions

How much smaller will my BMP be as AVIF?

Dramatically smaller, because you are comparing against no compression at all. The BMP side is pure arithmetic — 24-bit colour costs three bytes per pixel, so 4000x3000 pixels is about 36 MB before you consider content. The AVIF side depends on the image: flat graphics, screenshots, and line art collapse hardest, while dense photographic texture costs the most bits. As a reference point, MDN puts lossy AVIF at roughly half the size of the equivalent JPEG, and a JPEG of that bitmap would already be a small fraction of 36 MB.

Will I lose quality converting BMP to AVIF?

At the default Very High (Recommended) preset the loss is generally invisible at normal viewing sizes — that is the whole point of a modern lossy codec. But it is still lossy, and this page has no lossless option, so if you need pixel-exact fidelity the honest answer is that AVIF from this page is not the tool. Use BMP to PNG for a lossless copy and keep AVIF for delivery.

Does AVIF keep the transparency from a 32-bit BMP?

AVIF has a full alpha channel, so genuine transparency is preserved where the source actually has it. The catch is on the BMP side: although the format defines a 32-bit variant with alpha, the overwhelming majority of bitmaps are opaque 24-bit images, in which case your AVIF is simply opaque as well. Check the source depth before assuming transparency will survive.

Which browsers and apps can open AVIF?

Browser support is broad — about 94.7% of users worldwide, covering Chrome 85+, Firefox 93+, Safari 16.4+, Edge 121+, and Samsung Internet 14+. Outside the browser it is patchier: recent macOS releases preview AVIF natively, while on Windows you may need the AV1 image extension from the Microsoft Store before Photos and Explorer will show thumbnails. Older image editors and desktop tools frequently still cannot open it at all, which is the main practical argument against AVIF as a working file format.

Should I use AVIF or WebP for web images?

AVIF compresses harder. MDN's comparison puts AVIF at a median 50% reduction against a JPEG set, versus about 30% for WebP on the same images, and AVIF additionally supports 10- and 12-bit colour and HDR, which WebP does not. WebP's advantage is reach and speed: it is supported in slightly more browsers and encodes considerably faster. For a photo-heavy page where bytes matter, AVIF wins; for a build pipeline processing thousands of images under time pressure, WebP is the pragmatic choice.

Why does an AVIF take longer to produce than a JPEG?

Because AV1 encoding is genuinely more expensive computationally than JPEG's decades-old DCT pipeline — it evaluates far more prediction modes and partitioning options to find those extra savings. That cost is paid once, at conversion time, and repaid on every download afterwards. Larger bitmaps take proportionally longer, and since BMP uploads are big to begin with, transfer time is often the bigger share of the wait.

Is AVIF a sensible choice for print or archival masters?

No on both counts. Print workflows expect TIFF or high-quality PNG and often a CMYK profile, which AVIF is not designed for, and archival masters should never be lossy. AVIF is a delivery format — the copy you serve to browsers — not the copy you keep. Keep the original bitmap or a lossless PNG as your master and generate AVIF from it.

How are my files handled while converting?

Your bitmap is uploaded over an encrypted connection, converted on our servers, and the upload is deleted automatically after a few hours. There is no sign-up, no watermark, and files are never shared or made public. The practical limit on very large bitmaps is upload time rather than processing — an uncompressed BMP puts far more bytes on the wire than the AVIF you get back. Need the opposite direction, or a more widely readable target? See AVIF to JPG and BMP to JPG.