Will the QOI file be smaller than the source BMP?

Generally, yes. QOI encoding is always lossless, and since BMP source files are typically stored uncompressed, QOI's compact encoding usually shrinks the file, landing in roughly the same range as PNG.

Does the source BMP actually carry usable alpha?

It depends on the file. Older BITMAPINFOHEADER-based BMPs have no alpha channel, while newer V4/V5-header BMPs can carry real per-pixel alpha — but not every BMP-writing tool sets it even when the header supports it. QOI passes through whatever the source actually has.

Are my files uploaded?

No. Conversion runs locally in your browser and does not upload your file to Looty Tools servers.

What is validated before conversion?

The file must actually be a BMP — the tool checks the "BM" header bytes, not just the filename or extension, before decoding.

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BMP to QOI Converter

Convert BMP images to QOI (Quite OK Image), a fast, lossless, developer-focused format, directly in your browser.

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BMP to QOI processes files locally in your browser.

What BMP to QOI conversion does

Convert an old, typically uncompressed BMP image to QOI (Quite OK Image) directly in your browser — a fast, lossless, developer-friendly replacement for a legacy bitmap asset in a modern dev pipeline.

How to convert BMP to QOI

Choose a BMP file.
Select Convert & download.
Save the .qoi file from your browser downloads.

Why use this conversion

QOI's small, easy-to-implement specification makes it popular in tooling and pipelines that specifically read or write QOI, so a legacy BMP asset can be dropped straight into a fast, simple, developer-focused workflow.

Transparency and output quality

QOI supports a full alpha channel, and this tool passes through whatever alpha the browser decoded from the source BMP. QOI encoding is always lossless — every pixel from the source is reproduced exactly. Since BMP is typically stored uncompressed, this is generally a real size reduction, with output usually comparable to PNG.

Privacy and local processing

Processing occurs locally in the browser.
Files are not uploaded to Looty Tools for conversion.
Converted files remain on your device.

Limits and known issues

Input: BMP (.bmp) only, up to 25.0 MB and 8,192 px per side.
QOI is a developer-focused format with limited support in mainstream operating systems and browsers — it is intended for tooling and pipelines that read QOI directly.
Whether any alpha channel carries over depends on the source BMP's header: older BITMAPINFOHEADER files have none, while newer V4/V5-header files with real alpha data pass straight through losslessly.
Metadata is not preserved in the downloaded file.

Related tools

Guides

BMP to QOI FAQ

Why convert BMP to QOI?: QOI's small, easy-to-implement specification makes it popular in tooling and pipelines that specifically read or write QOI, so an old BMP asset can be dropped into a fast, simple, developer-focused workflow.
Will the QOI file be smaller than the source BMP?: Generally, yes. QOI encoding is always lossless, and since BMP source files are typically stored uncompressed, QOI's compact encoding usually shrinks the file, landing in roughly the same range as PNG.
Does QOI output keep transparency?: Yes, whatever the source has. QOI supports a full alpha channel, and this tool passes through whatever alpha the browser decoded from the source BMP.
Does the source BMP actually carry usable alpha?: It depends on the file. Older BITMAPINFOHEADER-based BMPs have no alpha channel, while newer V4/V5-header BMPs can carry real per-pixel alpha — but not every BMP-writing tool sets it even when the header supports it. QOI passes through whatever the source actually has.
Are my files uploaded?: No. Conversion runs locally in your browser and does not upload your file to Looty Tools servers.
What is validated before conversion?: The file must actually be a BMP — the tool checks the "BM" header bytes, not just the filename or extension, before decoding.