Make Image Black and White Online
Convert your color photos to beautiful black and white with NanoImage's free online tool. Our grayscale converter uses luminance-weighted algorithms to produce natural-looking monochrome images that preserve the tonal range and depth of your original photo. Adjust the grayscale intensity to find the perfect look — from subtle desaturation to full monochrome. Black and white photography has a timeless appeal that works beautifully for portraits, landscapes, street photography, and artistic projects. All processing happens in your browser with instant preview. No uploads, no installs, completely free.
Drag & drop your image here, or click to browse
Supports JPG, PNG, WebP, GIF, BMP
How to Use
- 1
Upload your image by dragging it into the upload area or clicking to browse.
- 2
Adjust the grayscale intensity slider to control how much color is removed (100% for full B&W).
- 3
Preview the result and click "Download" to save your black and white image.
Frequently Asked Questions
What algorithm is used for the conversion?
We use the luminance-weighted method (0.299R + 0.587G + 0.114B) which produces natural-looking grayscale that matches how the human eye perceives brightness.
Can I adjust the black and white intensity?
Yes! Use the intensity slider to go from subtle desaturation to full monochrome. At 50%, you get a nice muted color effect.
Will the black and white image be the same size?
The dimensions remain the same. The file size may be slightly smaller since grayscale images have less color information.
What's the difference between grayscale and desaturation?
Our tool uses luminance-weighted grayscale (0.299R + 0.587G + 0.114B) which mimics human perception of brightness. Simple desaturation averages RGB channels equally, which can look less natural.