HEIC to BMP Converter

This tool turns a HEIC file into a BMP file. Drop an image onto the upload zone or click it to browse your device, and a preview appears once the file has been decoded. Alongside the convert button you'll find a single convert button, since BMP output needs no extra settings. Nothing leaves your device: the file is read locally, converted locally, and the download link points at data held only in this browser tab.

Under the hood, the file is handed to that WebAssembly library, which decompresses it into raw pixels; a self-hosted WebAssembly build of libheif decodes the file, so this works the same way in Chrome, Firefox, Edge, and Safari. The library is loaded once from this site's own assets, not a third-party CDN. Those pixels then land on an HTML canvas, from which they are re-encoded as BMP. Because canvas has no built-in BMP writer, the pixel buffer is read with getImageData and packed by hand into a 24-bit BMP file header and row structure.

As with any browser-based converter there are limits worth knowing. On the input side, the first HEIC file on a page load has to wait for a ~1.4 MB decoder library to download once (it's then cached by the browser for the rest of the session), and a small number of unusual HEIC variants — multi-image bursts, depth maps, or exotic chroma formats — may not decode correctly through this library. On the output side, The BMP writer produces an uncompressed 24-bit file with no alpha channel, so transparency is flattened onto a white background and output files are noticeably large.