Add your BMP file
Drop one or more .bmp files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .bmp image to .avif re-encodes the pixels for a different balance of size, quality, and support. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Converting a .bmp image to .avif re-encodes the pixels for a different balance of size, quality, and support. A .bmp file is the Windows bitmap format: raw pixel rows written to disk with a small header and, in the common case, no compression at all. Its brute simplicity makes .bmp trivial to read and write from any programming language, which is why it persists in tooling, embedded systems, and quick debugging dumps.
An .avif file stores a still image (or sequence) coded with the AV1 video codec inside a HEIF-derived container. It is currently among the most efficient image formats deployed on the web, routinely beating JPEG by half at similar quality while adding HDR, wide gamut, and alpha. For this route the practical draw is best-in-class compression among widely supported web formats and 10/12-bit HDR and wide-gamut color, which JPEG cannot represent — balanced against encoding is much slower than JPEG or WebP, especially at high effort settings, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .bmp, no effective compression, so files dwarf PNG equivalents of the same image. Switching to .avif buys you best-in-class compression among widely supported web formats, which is why it is the better fit for serving hero images and photo galleries where bandwidth savings are significant. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Bitmap image (.bmp) | AVIF image (.avif) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Lossy — discards detail it judges invisible to shrink files |
| How it stores data | pixels are typically stored uncompressed; optional RLE encoding exists only for 4-bit and 8-bit palette images | encodes AV1 intra frames; both lossy and a mathematically lossless mode are defined |
| Strongest at | quick lossless dumps from code, since a writer takes minutes to implement | serving hero images and photo galleries where bandwidth savings are significant |
| Weak spot | no effective compression, so files dwarf PNG equivalents of the same image | encoding is much slower than JPEG or WebP, especially at high effort settings |
Drop one or more .bmp files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .avif in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AVIF is selectable, the route is real and validated.
Press Convert. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid AVIF file. Outputs keep the original filename with the .avif extension.
Some. Since bmp is lossless-oriented and avif is lossy-oriented, the encoder will discard detail it judges least visible; the quality slider controls how aggressive that is. Keep the original .bmp if you may need a pristine master later.
Yes — the .bmp file is processed inside your browser tab and never uploaded. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders. Close the tab and the file is gone from memory.
Chrome 85+ (2020), Firefox 93+ (2021), and Safari 16+ (2022) render AVIF natively, covering the overwhelming majority of current browsers. On the desktop, macOS 13+ and Windows (via the AV1 Video Extension) preview it, but plenty of older editing and printing software cannot open it yet.
Smaller, usually dramatically so — that is the main reason this route exists. The quality slider trades size against fidelity; the default sits at the point where most people cannot spot the difference.
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .bmp → .avif → .bmp is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.