Convert BMP to AVIF
BMP applies no compression at all and AVIF applies the most sophisticated compression available, so this conversion produces the largest size reductions of anything here — commonly 99% or more.
Best for: Legacy bitmaps that need to become genuinely small.
What to know
- Because BMP is uncompressed, the source is pristine — there is no existing generational loss to compound.
- BMP files are often very large in pixel dimensions, which makes AVIF's slow encoding slower still.
About BMP
Windows' uncompressed bitmap format. Essentially a raw pixel dump with a header.
- Usually no compression whatsoever — a 4000x3000 image is around 48 MB.
- Poor support outside Windows.
- No standard metadata support.
- Support:
- Most browsers, though it is rarely used on the web.
- Transparency:
- Inconsistent; usually absent.
About AVIF
Built on the AV1 video codec and standardised in 2019 — currently the strongest compression available in a widely supported still image format.
- The best quality-per-byte of any format here, typically by a wide margin.
- Handles gradients and flat colour without the banding JPEG produces.
- Wide colour gamut and HDR support built in.
- Full alpha, and it compresses that alpha well.
- Support:
- Chrome, Edge, Firefox, Opera and Safari 16+. Roughly 93% of users.
- Transparency:
- Full alpha, efficiently compressed.
Frequently asked questions
- How much smaller will my BMP get?
- Typically 99% or more. An uncompressed 48 MB bitmap commonly converts to a few hundred kilobytes with no visible difference.
Related conversions
Converting from something else? Convert any image to AVIF