BMP to AVIF: Complete Conversion Guide for Web & Storage

By Bill Crawford  ·  March 2026  ·  9 min read  ·  Last updated March 6, 2026

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What Is BMP?

BMP (Bitmap Image File) is one of the oldest raster image formats in existence, introduced by Microsoft with Windows 1.0 in 1987. It stores pixel data with no compression by default — every pixel is recorded as an explicit RGB or RGBA value in a simple grid. This simplicity made BMP the native format for Windows screenshots, icons in early versions of Windows, and desktop wallpapers throughout the 1990s and 2000s.

The defining characteristic of BMP — and its biggest practical problem — is file size. A BMP at 1920×1080 at 24-bit color occupies approximately 6 megabytes on disk. A 4K screenshot at 3840×2160 takes 24 megabytes. Because there is no compression, image content makes no difference: a solid white BMP and a complex photograph of the same dimensions are identical in file size. This made BMP workable when local storage was the only concern, but completely unsuitable for web delivery, email, or modern archival in volume.

What Is AVIF?

AVIF (AV1 Image File Format) is a modern image format published by the Alliance for Open Media in 2019. It uses the AV1 video codec — developed collaboratively by Google, Mozilla, Microsoft, Apple, and others — to compress still images. AV1 was designed as a royalty-free successor to HEVC and VP9, and its compression efficiency is genuinely superior to every older image format at typical web quality settings.

AVIF supports both lossy and lossless compression, full transparency (alpha channel), 10-bit and 12-bit wide color gamuts, HDR, and animation. Its compression algorithm identifies redundant information across regions of similar color and texture far more efficiently than JPG or PNG's older algorithms. At quality 80 — a standard web setting — AVIF typically produces files 50–80% smaller than an equivalent JPG and 80–95% smaller than an equivalent BMP.

Why Convert BMP to AVIF?

The core argument for BMP-to-AVIF conversion is extreme file size reduction. Consider a typical scenario: you have a screenshot or diagram captured in BMP format by a Windows application. At 1920×1080, it is 5.9 MB. Converting to AVIF at quality 80 will typically produce a file of 80–250 KB — a reduction of 95–98% — with no visible quality difference when viewed at normal screen resolution.

Beyond storage, AVIF is actually supported on the web, while BMP is not. No major browser loads BMP files as inline images in HTML. If you need to display a BMP on a website, you have no choice but to convert it first. AVIF is the best possible target format for that conversion when browser support is a concern — and as of 2026, Chrome, Firefox, Edge, and Safari 16+ all support it natively.

Additional reasons to convert include:

• Email attachments. A 6 MB BMP may be blocked by mail servers. A 150 KB AVIF is never a problem.
• Bulk archival. Converting a folder of 500 BMP screenshots from an older project to AVIF can reduce storage from 3 GB to under 100 MB.
• Design handoff. Many design tools and project management platforms do not accept BMP. AVIF is broadly accepted.
• CDN and bandwidth cost. Serving AVIF versus BMP (if you were somehow serving BMP) reduces bandwidth by 95%+.

BMP vs AVIF: Format Comparison

Choosing the Right Quality Setting

The quality slider in the converter controls the compression aggressiveness. Here is a practical guide to choosing the right value:

• Quality 90–95: Near-lossless. Suitable for product photography, medical imaging, or any image where fine detail cannot be compromised. File sizes are still 70–85% smaller than BMP, but larger than lower-quality settings.
• Quality 80–85 (recommended default): Excellent visual quality for the vast majority of images. Fine details and gradients are preserved. File sizes 90–95% smaller than BMP. Correct for almost all web deployment and general storage reduction.
• Quality 65–75: Visibly compressed on close inspection but acceptable for thumbnails, preview images, or social media where loading speed matters more than pixel accuracy.
• Quality 50–60: Aggressive compression for tiny file sizes. Suitable for low-priority previews. Visible compression artifacts in complex image areas.

For most BMP-to-AVIF conversions targeting web or storage reduction, start at quality 80 and only increase if you can spot visible artifacts at the intended display size. Viewing a 1920×1080 image at 100% zoom with a quality of 80 will almost always look identical to the original BMP.

AVIF vs WebP: Which Should You Choose?

If you are converting BMP for web delivery, you may be wondering whether to use AVIF or WebP. Both are superior to JPG and PNG for most web images. The key differences:

• Compression efficiency: AVIF is generally 20–30% more efficient than WebP at the same visual quality. For a given file size budget, AVIF produces higher quality.
• Browser support: WebP has slightly broader support (including IE11 with a polyfill). AVIF has 90%+ modern browser support as of 2026. Safari added AVIF support in version 16 (2022).
• Encoding speed: AVIF encoding is slower than WebP in some environments. For batch conversions in the browser, this is rarely noticeable for individual files.
• HDR and wide color: AVIF supports 10-bit and 12-bit color; WebP is limited to 8-bit. For HDR content, AVIF is the only choice.

Recommendation: Use AVIF as your primary target. If you need a fallback for older browser support, the HTML <picture> element allows you to serve AVIF to modern browsers and WebP or JPG to older ones.

AVIF Browser Support in 2026

AVIF support has reached mainstream status. Chrome has supported AVIF since version 85 (released August 2020). Firefox added AVIF support in version 93 (October 2021). Edge supports AVIF since version 121. Safari — the last major holdout — added AVIF support in Safari 16 (released September 2022), meaning all iPhones running iOS 16 or later display AVIF without any fallback needed.

The practical implication: if you are building or updating a website in 2026, you can serve AVIF as your primary image format with confidence. A JPG fallback via <picture> is good practice for the small percentage of users on very old browsers, but AVIF should be the default delivery format for all new image assets.

When to Use Lossless Instead of AVIF

Not every BMP should become a lossy AVIF. Consider keeping lossless formats in these cases:

• Source files for further editing. If the BMP is a working file you will open and re-export, use lossless PNG. Re-encoding lossy images introduces cumulative quality degradation.
• Pixel-perfect diagrams or pixel art. Images with sharp pixel-level detail — maps, circuit schematics, pixel art — may show AVIF compression artifacts around sharp edges. PNG lossless handles these better.
• Legal or archival documents. Screenshots used as evidence or permanent records should be lossless. Use PNG rather than AVIF for these.
• Images with fine text at small sizes. Text rendered at small sizes can show visible softening with lossy AVIF compression. Use quality 90+ or PNG for screenshots containing small text.

Conversion Methods

Browser-Based (No Installation)

The BMP to AVIF Converter on this site handles everything client-side. Drop your BMP files, set your quality, click convert, and download. No account, no upload, no file size limits — processing happens entirely in your browser using the Canvas API.

ImageMagick (Command Line)

For scripted batch conversion on macOS or Linux with ImageMagick and libavif installed:

magick input.bmp -quality 80 output.avif

To batch convert a directory:

for f in *.bmp; do magick "$f" -quality 80 "${f%.bmp}.avif"; done

FFmpeg

FFmpeg with libaom-av1 can encode AVIF from BMP:

ffmpeg -i input.bmp -c:v libaom-av1 -still-picture 1 -crf 25 output.avif

Lower CRF values produce higher quality; 25–35 is a typical range for web use.

Tips & Best Practices

• Always inspect at 100% zoom. Lossy compression artifacts are invisible at thumbnail size but can be visible when zoomed. Review output at the intended display size before deploying.
• Use the picture element for production. Serve AVIF with a WebP or JPG fallback: <picture><source srcset="image.avif" type="image/avif"><img src="image.jpg" alt="..."></picture>
• Preserve originals. Keep the original BMP (or convert to lossless PNG) before discarding the source. Once re-encoded to lossy AVIF, you cannot perfectly recover the original pixels.
• Use ZIP for batch downloads. When converting 5 or more files, enable ZIP download to avoid multiple browser download dialogs.
• Check file size ratio. A good BMP-to-AVIF conversion at quality 80 should produce a file 5–15% the size of the input BMP. If the ratio is higher, consider lowering quality; if the image is very simple (solid colors), AVIF may produce a nearly lossless result at much smaller sizes.

Frequently Asked Questions

Is AVIF always better than PNG for converted BMP files?

For photographs and complex images, AVIF lossy compression outperforms PNG significantly in file size with minimal visible quality loss. For simple pixel art, line diagrams, or images that require pixel-perfect lossless output, lossless PNG compression may be more appropriate — AVIF lossless is also possible but less efficient than PNG for these cases.

What quality setting is best for web images?

Quality 80 is the widely recommended starting point for web images. It produces files roughly 5–10% the size of the original BMP with visually indistinguishable results at screen resolution. Increase to 85–90 for images with fine text or product photography where subtle details matter.

Can I use AVIF on a website today?

Yes. AVIF has over 90% browser market share as of 2026. Use the HTML <picture> element with a JPEG or WebP fallback for the small percentage of users on legacy browsers, and AVIF as the primary <source>.

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