Convert BMP to PNG in seconds – right in your browser
Drop your BMP file into the tool above and download a crisp PNG instantly. No sign-up, no software to install, and your image never leaves your device – everything happens on your computer using the browser's built-in canvas.
BMP files are huge. A single uncompressed bitmap can easily be 5–10× larger than the same image saved as PNG. Converting to PNG gives you lossless compression – identical quality, a fraction of the file size, and broad support across every browser, app, and operating system.
How to convert BMP to PNG
- Choose your file. Click the upload area above or drag your .bmp file onto it.
- Conversion happens automatically. The canvas reads your bitmap and re-encodes it as PNG in your browser – no server involved.
- Download the result. Hit the Download button and save your new .png file.
Worked example
Say you have a scanned logo saved as logo.bmp at 800 × 600 pixels. The raw BMP file is around 1.4 MB. After converting to PNG the same image typically comes out at 80–200 KB – often 80–90% smaller – with zero loss in quality. Transparent pixels (if your BMP source supports them) are preserved in the PNG output.
| Format | Typical size (800×600 image) | Lossless? | Transparency? |
|---|---|---|---|
| BMP (24-bit) | ~1.4 MB | Yes | No (standard) |
| PNG | ~100–200 KB | Yes | Yes (alpha channel) |
How to do this in Python or Node.js
If you need to automate BMP-to-PNG conversion in a script or CI pipeline, here are two minimal, copy-pasteable snippets.
Python (Pillow) – install with pip install Pillow:
from PIL import Image
img = Image.open('logo.bmp')
img.save('logo.png') # Pillow detects PNG from the extension
Node.js (sharp) – install with npm install sharp:
const sharp = require('sharp');
sharp('logo.bmp')
.png()
.toFile('logo.png')
.then(() => console.log('Done!'));
Both libraries handle the BMP header, bit-depth conversion, and PNG encoding in one step. Pillow's official docs are at pillow.readthedocs.io; sharp's docs live at sharp.pixelplumbing.com.
How it works under the hood
The tool uses the browser's Canvas API (MDN Canvas API docs). Your BMP is drawn onto a hidden <canvas> element, then canvas.toBlob('image/png') encodes the pixel data as a lossless PNG. The resulting file is handed directly to your browser's download mechanism. Nothing is sent to any server.
BMP stores raw, uncompressed pixel values (typically 24 bits per pixel). PNG applies DEFLATE compression (a zip-style algorithm) plus smart per-row filtering – so the file shrinks dramatically while every single pixel stays identical.
When to convert BMP to PNG – and when not to
Good reasons to convert:
- Reducing file size for sharing, email, or web upload – PNG is universally accepted, BMP rarely is.
- Keeping sharp edges on logos, screenshots, text, or icons without any compression artifacts.
- Adding transparency – PNG supports an alpha channel; most BMP variants do not.
- Compatibility: PNG is supported natively by every modern browser, OS, and design tool; BMP is mostly a Windows legacy format.
Skip PNG if:
- You are converting a photograph and file size matters most – JPG (with quality ~80) is far smaller than PNG for photos with no noticeable quality loss.
- You are targeting a modern web page – WebP is smaller than PNG for most images while staying lossless when you need it. Our WebP converter handles that.
Ready to shrink your bitmap? Drop the file into the tool above and download your PNG in one click.