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ImageConverter

Secure server conversion

BMP to AVIF Converter

Convert a Windows BMP into AVIF, and you move from the least efficient image format in common use to the most efficient. The drop in size is dramatic: a photograph went from 360 KB to 39 KB in testing, and a simple graphic from 720 KB to about 1 KB. That makes old bitmaps practical for the web for the first time.

Deleted automatically Uploads removed within 30 minutes

Drag and drop your BMP images here

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

Up to 20 MB per file Batch ready

75
Smaller file More detail
Presets:

Higher keeps more detail; lower makes a smaller file. Applies to images you add after changing it.

Step by step

How to convert BMP to AVIF in 3 steps

  1. Add your BMP

  2. Adjust quality if you like — the default suits most images

  3. Download your AVIF

Format comparison

BMP vs AVIF

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

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

Two ends of the efficiency scale

A BMP stores three bytes for every pixel with no compression at all, so its size depends only on its dimensions. AVIF, standardised in 2019, is built on the AV1 video codec and uses decades of compression research to store the same picture in a small fraction of the space.

Measured at this page's default quality setting:

  • A photograph: 360 KB → 39 KB, 89% smaller.
  • A simple graphic of flat colours: 720 KB → 1.0 KB — around seven hundred times smaller.

Flat areas are where AVIF excels. It can describe a large region of one colour with almost no data, which is exactly what the bitmap was spending most of its bytes on.

This is lossy compression

Unlike BMP, AVIF achieves those savings by discarding detail the eye is unlikely to notice. At the default setting a photograph looks essentially unchanged, but it is not a bit-for-bit copy. For an exact copy, use BMP to PNG instead: lossless, though far larger than AVIF.

Why AVIF for old bitmaps

BMPs are too large to put on a website: a single 1920 × 1080 bitmap is about 6.2 MB. AVIF turns the same image into something that loads instantly, and every current major browser displays it — Chrome, Firefox, Safari and Edge.

Quality

Quality and file size

AVIF's quality scale is not JPEG's. Numbers that would look rough as a JPEG are often clean as AVIF, so the default here sits in the middle of the range.

  • 75, the default — photographs look essentially unchanged, and graphics stay crisp.
  • 85–100 — for images that will be edited again or examined closely. Larger, closer to the original.
  • 50–65 — for thumbnails and backgrounds where the smallest file matters most.

Screenshots and text

Old BMPs are very often screenshots. Lossy compression can soften very fine text and single-pixel lines slightly. If a screenshot's text must stay perfectly sharp, raise the quality — or use PNG, which keeps every pixel exact and is still far smaller than the BMP.

Very large bitmaps

A BMP's size depends only on its dimensions: three bytes per pixel, so a 4000 × 3000 bitmap is about 36 MB whatever it shows. Each file can be up to the size shown on the upload area. If a bitmap is bigger, save it as PNG in Paint first — nothing is lost — and convert that with PNG to AVIF.

When BMP to AVIF makes sense

  • Putting old images on a website, where file size decides how fast pages load.
  • Reclaiming storage from folders of bitmaps when exact pixel copies are not required.
  • Sharing images that are too large to email as BMP.
  • Modernising legacy application assets for a web version of old software.

AVIF, WebP or PNG?

  • AVIF — smallest files. Ideal for websites targeting current browsers.
  • WebP — noticeably larger, but supported by more software outside browsers and much faster to create. Measured on a 3000 × 2000 photograph — one previously saved as a JPEG, which makes it compress more easily than a camera original: 102 KB as WebP against 68 KB as AVIF, but created in about 0.6 seconds instead of 3.6.
  • PNG — lossless, so every pixel is exact. Much larger than AVIF, still far smaller than BMP.

Compatibility outside the browser

AVIF is displayed by every current major browser, but support elsewhere is still uneven: some image viewers, office software and older phones cannot open it. For files you will send to other people rather than serve on a website, JPG or PNG is the safer choice.

Going the other way

AVIF to BMP reverses this, for legacy software that reads only bitmaps.

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

BMP to AVIF: frequently asked questions

How much smaller will my file be?

Dramatically. At the default setting a photograph went from 360 KB to 39 KB, and a simple graphic from 720 KB to about 1 KB. BMP stores every pixel uncompressed; AVIF is the most efficient image format in common use.

Does converting to AVIF lose quality?

A little: AVIF is lossy, and discards detail the eye is unlikely to notice. At the default setting photographs look essentially unchanged. For an exact pixel copy, convert to PNG instead.

Will the text in my screenshot stay sharp?

Lossy compression can slightly soften very fine text and single-pixel lines. Raise the quality setting, or use PNG, which keeps every pixel exact and is still far smaller than the BMP.

Can every browser show AVIF?

Every current major browser displays AVIF — Chrome, Firefox, Safari and Edge. Support outside browsers is patchier, so for files you send to people, JPG or PNG is safer.

Should I choose AVIF or WebP?

AVIF gives the smallest files — on a 3000 × 2000 photo, 68 KB against 102 KB as WebP. WebP opens in more software outside browsers and was about six times faster to create. For a modern website, AVIF; where compatibility or speed matters more, WebP.

Is my image uploaded?

Yes. The conversion runs on our server so that it works the same on every device. Your upload is deleted the moment the AVIF is made, the AVIF is deleted as soon as you download it, and no one looks at your images.

Keep going

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