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ImageConverter

Secure server conversion

AVIF to BMP Converter

Convert an AVIF image into a Windows BMP bitmap. AVIF is the most efficient image format in common use and BMP the least, so for a photograph this is the biggest size increase of any conversion here: about fifteen times in testing. The pixels come through faithfully — it is simply the newest image technology being stored the oldest possible way.

Deleted automatically Uploads removed within 30 minutes

Drag and drop your AVIF images here

Add several at once. Each file is processed and then deleted from our server.

Up to 20 MB per file Batch ready

#ffffff

BMP cannot store transparency, so it is filled with this colour.

Step by step

How to convert AVIF to BMP in 3 steps

  1. Add your AVIF file

  2. Choose a background colour for any transparent areas

  3. Download your BMP

Format comparison

AVIF vs BMP

AVIF (AV1 Image File Format)

Lossy or lossless

The newest widely supported web format, built on the AV1 video codec and designed for the smallest files.

  • Usually the smallest file at a given visual quality
  • Supported by current Chrome, Edge, Firefox and Safari
  • Slow to encode, and unsupported by much older software

BMP (Windows Bitmap)

Uncompressed

An early Windows format that stores pixels more or less raw, with little or no compression.

  • Read by old and embedded software that knows nothing newer
  • No compression artefacts
  • Very large files for the image size

Thirty-four years of compression, undone

AVIF, standardised in 2019, is built on the AV1 video codec and packs photographs into remarkably few bytes. BMP, from 1985, writes out three bytes for every pixel.

Measured:

  • A photograph: 24 KB as AVIF → 361 KB as BMP. About fifteen times.
  • A simple graphic: 1.7 KB → 720 KB. Around four hundred times.

A photo grows more from AVIF than from any other source — more than from JPG, WebP or HEIC — because AVIF compressed it hardest in the first place.

What each AVIF feature becomes

AVIF's advantages mostly have nowhere to go in a bitmap:

  • Higher bit depth. AVIF can store 10 or 12 bits per channel, which matters for HDR and smooth gradients. BMP stores 8. The image is reduced to 8 bits per channel.
  • Transparency. AVIF has full alpha; a standard BMP has none. Transparent areas are blended onto the background colour you choose.
  • Animation. AVIF can hold image sequences; a BMP holds one image. The result is a single still image.

The decoded image, exactly

AVIF is almost always lossy, and converting does not recover what it discarded. The BMP is a precise record of the image as AVIF decodes it — no sharper, no smoother, just far larger.

What happens to transparent pixels when converting AVIF to BMP?

BMP cannot store transparency, so transparent and semi-transparent areas are blended onto a solid background before the file is saved — the colour you choose above, #FFFFFF by default. Keep your original AVIF if you may need the transparency again.

Quality

Quality and file size

There is no quality setting. BMP is uncompressed and records the decoded image exactly, reduced to 8 bits per channel.

Transparency and the background colour

Partly-transparent areas blend into your chosen colour correctly, so soft edges do not gain hard outlines — but the colour becomes part of the picture. Choose the one the image will sit on. Old software that reads BMP often mishandles bitmap transparency, so an explicit colour is the reliable option.

Why AVIF needs converting at all

Current browsers display AVIF without trouble. Almost everything else lags: many image viewers, office suites, older operating system previews, and nearly all legacy and embedded software cannot open it. An AVIF saved from a website is often unusable the moment it leaves the browser.

A smaller option, if the software allows

  • AVIF to PNG — lossless, keeps transparency, and a fraction of the BMP's size.
  • AVIF to JPG — the most compatible small format for photographs.

Choose BMP only when the destination specifically requires it.

Where this conversion is needed

  • Legacy desktop software that reads bitmaps but predates AVIF by decades.
  • Embedded and industrial displays with simple image decoders.
  • Game engines and modding tools expecting bitmap textures.
  • Scientific and lab software processing raw pixel data.

How large the file will be

Always width × height × 3 bytes, plus a small header, whatever the image shows:

  • 1200 × 800 — about 2.9 MB.
  • 1920 × 1080 — about 6.2 MB.
  • 3840 × 2160 (4K) — about 24.9 MB.

If you have the original

AVIF files are nearly always generated from something else — a photograph, a design export, a build pipeline's master image. If you have that original, converting it straight to BMP avoids AVIF's compression losses entirely and gives a better bitmap.

Going the other way

BMP to AVIF reverses this and produces some of the largest savings on the site, which is a good use of AVIF's strengths.

What happens to your file

Browsers cannot write BMP files, so this runs on our server. Your upload is deleted the moment conversion finishes, the result is deleted as you download it, and anything abandoned is swept automatically.

Privacy

What happens to your file

This tool runs on our server, so it works the same on every phone and computer. Your file is uploaded, and this is exactly what happens to it:

  • Stored outside the public web root under a random name, never under your file's name.
  • Processed, with the original upload deleted immediately — whether it succeeded or failed.
  • The result sits behind a signed link that only you receive, which stops working after 20 minutes, and the file is deleted the moment you download it.
  • Anything never collected is deleted automatically within 30 minutes.
  • The image itself is never logged or kept. If a conversion fails, we record the formats involved and the error — not the file.
  • Camera metadata, including any GPS coordinates recording where a photo was taken, is removed from the result. Only the rotation needed to show the image the right way up is kept.

Questions & answers

AVIF to BMP: frequently asked questions

Why is the BMP fifteen times bigger?

AVIF is the most efficient image format in common use, built on the AV1 video codec; BMP stores three raw bytes per pixel with no compression. Measured, a 24 KB AVIF photo became a 361 KB BMP. Photos grow more from AVIF than from any other source because AVIF compressed them hardest.

What happens to 10-bit or HDR AVIF images?

They are reduced to 8 bits per channel, which is all a BMP stores. Standard images look the same; the extra precision that helps HDR and very smooth gradients does not survive.

What happens to transparency?

Transparent areas are blended onto the background colour you choose, with soft edges fading into it correctly. The colour becomes part of the image, so pick the one it will sit on.

Can an animated AVIF be converted?

The result is a single still image, since a BMP holds one image.

Will the BMP have better quality than the AVIF?

No. AVIF is almost always lossy, and the BMP records the decoded image exactly, without recovering anything. If you have the image the AVIF was made from, convert that instead.

Is there a smaller alternative?

If the destination accepts it, PNG keeps every pixel and transparency at a fraction of the size, and JPG is the most compatible small option for photos. Use BMP only when something specifically requires it.

Keep going

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