HEIC to BMP Converter

Some programs — older Windows software, kiosk and signage players, embroidery and laser-engraving tools, microcontroller projects — only take plain BMP bitmaps, while iPhones save photos as HEIC. This converter decodes each HEIC photo in your browser and writes a standard Windows BMP. A max size option keeps the bitmaps manageable, because BMP stores every pixel uncompressed.

How to use this tool

1. Choose one or more HEIC or HEIF photos.
2. Pick 24-bit colour (most compatible), 32-bit or 8-bit greyscale.
3. Optionally set a max size such as 1920 px and the DPI to store.
4. Download the BMPs, or all of them as a ZIP.

Formula

BMP size = 54 + height × row bytes, where row = width × 3 rounded up to a multiple of 4 (24-bit). For 8-bit greyscale add a 1,024-byte palette and use 1 byte per pixel.

Photos are turned upright as on the phone before saving. iPhone photos have no transparency, so 24-bit is the natural choice; for a rare transparent HEIF, 32-bit keeps the alpha channel while 24-bit and 8-bit fill it with the colour you choose. Safari decodes HEIC itself; other browsers use a built-in HEIF decoder with a time limit, so a file that stalls is reported instead of freezing the page.

Example

A 4032 × 3024 px iPhone photo has rows of 4032 × 3 = 12,096 bytes, so the 24-bit BMP is 54 + 3024 × 12,096 = 36,578,358 bytes (about 34.9 MB). With a max size of 1920 px it becomes 1920 × 1440 px and 54 + 1440 × 5,760 = 8,294,454 bytes (about 7.9 MB).