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Turn your BMP images into AVIF right in the browser — this tool will shrink each file and hand it back in seconds, with nothing uploaded to any server. BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. AVIF is the newest AV1-based format with the best compression available today, often half the size of JPEG. AVIF adds an alpha channel, so you gain transparency support that BMP never had. Free, private, unlimited, and watermark-free.
How to Convert BMP to AVIF
Add your BMP files
Drag and drop, or click to browse. You can convert several at once — they are processed together, right here in your browser.
Convert to AVIF
Pick a quality level if you want to trade a little detail for a smaller file, then press Convert. Encoding is instant for most images.
Download
Save each AVIF file, or grab them all as a ZIP. Nothing was ever uploaded, so nothing needs deleting.
Why convert BMP to AVIF?
The main reason is modern web delivery, offering the smallest files at a given quality with transparency and HDR. BMP excels at exact pixel data with zero compression, but when you need transparency, AVIF is the better fit. This tool makes that switch instantly, right in your browser.
What happens to quality?
Converting into AVIF re-encodes the image, and because AVIF is lossy you control the trade-off with the quality setting. At high quality the difference is invisible.
A note on file size
Expect the AVIF file to be noticeably smaller than your BMP.
About BMP
BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. Best for exact pixel data with zero compression, occasionally required by legacy Windows software.
About AVIF
AVIF is the newest AV1-based format with the best compression available today, often half the size of JPEG. Best for modern web delivery, offering the smallest files at a given quality with transparency and HDR.
Common Uses for BMP to AVIF
- Converting BMP to AVIF for a project that specifically requires AV1 Image File Format files, where BMP is not accepted.
- Preparing images for the web, where AVIF keeps file sizes small and pages fast.
- Batch-converting a whole folder of BMP images to AVIF at once, instead of doing them one at a time.
- Switching a Bitmap export into AVIF so it opens correctly in the tools your team actually uses.
- Compressing large BMP images into smaller AVIF files to save storage and bandwidth.
BMP vs AVIF: Key Differences
| Aspect | BMP | AVIF |
|---|---|---|
| Compression | Lossless | Lossy or lossless |
| Transparency | Not supported | Supported |
| Animation | Not supported | Supported |
| Colour depth | 24-bit uncompressed colour | up to 12-bit colour with alpha |
| Typical file size | Large | Small |
| Best used for | exact pixel data with zero compression | modern web delivery |
Tips & Things to Know
Check the file size after converting
Expect the AVIF file to be noticeably smaller than your BMP. If size matters for your use case, the before-and-after figures shown above tell you exactly what changed, so there are no surprises when you upload or share the result.
Add transparency support
Because AVIF supports an alpha channel, the result can hold transparency even though BMP itself is always fully opaque. Areas stay on whatever background the BMP shows.
Everything stays on your device
This converter runs entirely in your browser using your own processor. Your BMP files are never uploaded, stored, or seen by anyone, which makes it safe for private photos, client work, and confidential documents. When you close the tab, nothing remains.
Tune the quality if you need to
For AVIF you can trade a little detail for a smaller file using the quality slider. At around 90% the difference is invisible to the eye, while the file can be much smaller — useful for web images and email attachments.
Frequently Asked Questions
How do I convert BMP to AVIF for free?
Add your BMP file above and press Convert. The AVIF download appears in seconds. It is completely free, with no signup, no limits and no watermark.
Is my BMP uploaded to a server?
No. The entire conversion runs inside your browser using your device's own processor, so your images never leave your computer. That matters for private photos and confidential work.
Can I convert multiple BMP files at once?
Yes. Add as many as you like and they are converted in one batch, then offered individually or as a single ZIP download.
Will converting to AVIF reduce quality?
Only if you choose a lower quality setting. At high quality the result is visually identical to the original.
Does AVIF support transparency?
Yes, AVIF supports an alpha channel, so transparent areas in your image are preserved.
Why is my AVIF file a different size than the BMP?
Different formats compress differently. Expect the AVIF file to be noticeably smaller than your BMP.
What is the difference between BMP and AVIF?
BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. AVIF is the newest AV1-based format with the best compression available today, often half the size of JPEG. That difference is what this conversion is really about.
Is there a file size limit?
Because processing happens in your browser, very large images depend on your device's memory, but typical photos convert instantly. Nothing is capped by an upload limit.
Do I need to install anything?
No. This works in any modern browser on any device — Windows, Mac, Android or iPhone — with nothing to install.
Is this BMP to AVIF converter really free?
Completely free, forever, with no account, no watermark and no hidden premium wall.
100% free · No signup · No watermark · Files never leave your browser
Last updated: July 18, 2026 · FlipMyFormat Convert BMP to AVIF
Written and maintained by the FlipMyFormat team · Runs entirely in your browser