Convert BMP to PNG on Mac — Free Methods That Work in Safari and Preview

Mac handles BMP files well but doesn't natively encourage you to keep them — Preview can convert them to PNG in a few clicks, and the browser-based converter works perfectly in Safari with no download needed. Here's how to do it both ways.

Method 1: Browser Tool in Safari — Works on Any Mac

1. Open the BMP to PNG converter (link below) in Safari, Chrome, or Firefox on your Mac
2. Drag your BMP files from Finder into the drop zone on the page
3. Click "Convert to PNG"
4. Download the converted PNG files — or use "Download All as ZIP" for multiple files

This works on any macOS version and processes files entirely in your browser. Nothing is uploaded to any server. You can even use it in private browsing mode if you prefer.

Method 2: Preview — Built Into Every Mac

1. Double-click the BMP file — it opens in Preview automatically
2. Go to File > Export
3. In the Format dropdown, select PNG
4. Adjust the filename if needed, then click Save

For batch conversion in Preview: Open multiple BMP files at once (select them all in Finder, right-click, Open with Preview). In Preview's thumbnail sidebar, select all pages (Cmd+A). Then go to File > Export Selected Images, choose PNG as the format, and pick a destination folder.

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Method 3: Terminal with sips (macOS Built-In)

macOS ships with a command-line image processor called sips that can batch-convert BMP files without any additional software:

cd /path/to/your/bmp/files
for f in *.bmp; do sips -s format png "$f" --out "$(basename $f .bmp).png"; done

This converts every BMP in the current folder to PNG. Replace /path/to/your/bmp/files with your actual folder path. The original BMP files are not deleted — new PNG files are saved alongside them.

Can Mac Open BMP Files Without Converting?

Yes. Preview, Photos, and most image editors on Mac can open BMP files directly. The question is usually whether you want to keep them as BMP. Since PNG files are 5–20x smaller with identical quality, converting makes sense for storage and sharing.

BMP files sent from Windows systems open fine on Mac. If you're receiving BMP files regularly and want them in a more efficient format, either method above converts them in seconds.

Frequently Asked Questions

Why does my Mac say it can't open a BMP file?

This is rare — Preview supports BMP. If you get an error, the BMP file may be corrupt or use an unusual variant (1-bit monochrome or 16-bit color). Try the browser converter, which supports more BMP variants.

Does converting BMP to PNG work on macOS Ventura/Sonoma?

Yes, all methods described above work on any modern macOS version including Ventura, Sonoma, and Sequoia. Preview's export format list and the sips command both support PNG on all versions.

Is PNG quality the same as BMP on Mac?

Identical. BMP and PNG are both lossless formats. Converting between them preserves every pixel exactly. The PNG will look the same and open faster since it's much smaller.