BMP to AVIF Converter — Convert BMP to AVIF Online
Turn a bulky uncompressed bitmap into an AVIF a fraction of its size. Drop your file below and pick AVIF as the output format — free, private, and entirely in your browser with no upload required.
Drop images here or click to browse
Supports HEIC, WEBP, AVIF, BMP, TIFF, SVG, GIF, ICO, PDF, JPG, PNG
100% Private — Your files never leave your device
All conversion happens directly in your browser using JavaScript. Nothing is uploaded to any server. Your images stay on your computer the entire time.
Why Convert BMP to AVIF?
Because BMP is the most wasteful raster format in common use and AVIF is among the most efficient. A 24-bit BMP spends about 3 bytes on every pixel and applies no compression at all, so its size is fixed by the image's dimensions — a blank white frame costs exactly as much as a detailed photograph. AVIF compresses the same pixels with the AV1 codec's intra-frame tooling.
The savings are not incremental. Taking the 1600 × 2000 photograph from this site's own homepage and running it through the converter above:
- As a 24-bit BMP: 9,600,054 bytes — fixed by the pixel count, whatever the picture shows
- As AVIF at the default 92% quality: 250.9 KB, or 97.3% smaller
- As AVIF at 50% quality: 41.5 KB, or 99.6% smaller
That is the whole reason this conversion exists. BMP earns its keep when a piece of legacy software demands raw pixels; the moment the file has to cross a network, sit in a web page, or live in cloud storage, those megabytes are pure cost. If you want the file smaller but need every pixel preserved exactly, convert BMP to PNG instead — PNG discards nothing and still shrinks the bitmap substantially.
BMP vs JPG vs WebP vs AVIF
Every number below is the same source photograph — 1600 × 2000 pixels, 3.2 megapixels — encoded by this converter and measured, not estimated. As a BMP it is 9.2 MB at every setting, because the quality slider has nothing to act on.
| Quality setting | JPG | WebP | AVIF | AVIF vs BMP |
|---|---|---|---|---|
| 50% | 108.6 KB | 54.1 KB | 41.5 KB | 99.6% smaller |
| 75% | 219.7 KB | 81.5 KB | 124.2 KB | 98.7% smaller |
| 92% (default) | 310.6 KB | 245.5 KB | 250.9 KB | 97.3% smaller |
Two things worth reading off that table. AVIF beat JPG at every setting — by 19% at the default and by 62% at 50% quality — so if you were going to make a JPEG, the AVIF is smaller. Against WebP the answer depends on how hard you are compressing: AVIF pulled well ahead at 50% quality, while WebP came out slightly smaller on this photo at the top of the range.
The catch is that a “quality” number is not a shared scale. Each codec maps it onto its own quantiser, so the 75% row compares three files that do not look alike — AVIF is aiming much higher there than WebP is. Judge the result with your own eyes, and remember that a different image will land on different numbers. For a closer look at how the two modern codecs differ, see WebP vs AVIF.
How to Convert BMP to AVIF
- Drag your BMP file into the drop zone, or click to browse and select it.
- Choose AVIF from the Output Format menu.
- Lower the Quality slider if you want a smaller file, or raise it to stay closer to the original.
- Download the AVIF — it's saved straight to your device.
You can drop several bitmaps at once and take them away together as a ZIP. Nothing is uploaded: the AVIF encoder is compiled to WebAssembly and runs on your own machine, so even confidential scans and screenshots never leave your computer. Expect a large bitmap to take a few seconds — AV1 compression is doing real work.
When AVIF Is the Wrong Choice
AVIF wins on size, and size is not always what matters. Reach for something else when:
- The file has to open in older software. Windows Photos needs the AV1 Video Extension, and many desktop editors will simply refuse an AVIF.
- You need every pixel preserved. AVIF is lossy at the default setting; BMP to PNG is lossless and still cuts the size sharply.
- You are archiving a master copy. Keep the untouched original and compress a derivative from it.
- Something downstream demands a bitmap. That is the one job BMP is still good at.
And if you already have AVIF files that need to be readable anywhere, AVIF to JPG handles the return trip.
Frequently Asked Questions
How much smaller will the AVIF be than the BMP?
Enormously smaller. A 24-bit BMP spends 3 bytes on every pixel and compresses nothing, so a 1600×2000 photo is always 9,600,054 bytes. Converting that photo here produced a 250.9 KB AVIF at the default 92% quality — 97.3% smaller — and a 41.5 KB AVIF at 50% quality, which is 99.6% smaller. Flat graphics and screenshots compress further still than photographs do.
Does converting BMP to AVIF lose quality?
At the default setting AVIF is a lossy format, so yes — it discards detail to shrink the file. In practice the loss is very hard to see: the 92% AVIF of our test photo measured 52.9 dB PSNR against the original bitmap, which is the range normally called visually lossless. Because BMP is uncompressed, this is also the first generation of loss the pixels have suffered, which is the best possible starting point. Push the Quality slider higher if you want to stay closer to the original.
Can I convert BMP to AVIF for free?
Yes. This BMP to AVIF compressor is completely free with no sign-up, watermarks, or file limits. The AVIF encoder is libavif compiled to WebAssembly and it runs inside your browser, so your bitmaps are never uploaded to a server.
Why is the first conversion slower than the others?
The AVIF encoder is a 3.5 MB WebAssembly module that downloads the first time you pick AVIF, then stays in memory for the rest of the session. Encoding itself is also genuinely slow work: AVIF uses the AV1 codec's intra-frame compression, which searches much harder for redundancy than JPEG or WebP do. A multi-megapixel bitmap takes a few seconds. That search is exactly what buys you the small file.
Will an AVIF file open everywhere?
In browsers, essentially yes: Chrome, Edge, and Opera have supported AVIF since 2020, Firefox since version 93, and Safari since 16.4. Desktop software is patchier — Windows needs the AV1 Video Extension before Photos will show an AVIF, and plenty of image editors still cannot open one. If the file has to open absolutely anywhere, convert to PNG or JPG instead.
Does AVIF keep the transparency in my BMP?
AVIF supports an alpha channel, but the 24-bit BMPs this converter reads and writes do not carry one, so in practice there is no transparency to preserve. If your source image has transparency and you need to keep it, start from a PNG or WebP rather than a BMP.