Image Grayscale Converter
Convert any color image to black and white in your browser.
Drop your image here
or click to browse · max 50 MB
Settings
Converts your image to black and white (grayscale). Upload an image and click Convert.
wasm-vips (~5MB) will be downloaded on first use and cached by your browser.
Image Grayscale Converter
Converts color images to black and white (grayscale). Removes all color information while preserving luminance values, creating a classic monochrome look. Uses wasm-vips for accurate color-to-grayscale conversion with proper luminance weighting.
What is it used for?
- Creating classic black and white photos from color originals
- Preparing images for printing on monochrome printers
- Reducing file size by removing color channels
- Creating consistent visual style for design projects
- Preprocessing images for computer vision or OCR
Step-by-Step Guide
- Click the upload area or drag and drop your image
- Choose your output format (PNG, JPEG, WebP, or AVIF)
- Click Convert to create the grayscale version
- Preview and download the result
How it works
Upload a color image and click Convert. wasm-vips converts the color space from RGB to grayscale using perceptual luminance weighting (ITU-R BT.601). Download in your preferred format.
Tips & Best Practices
- Grayscale PNG files are significantly smaller than color PNGs
- Use JPEG output for photographs and PNG for graphics
- Adjust brightness and contrast after converting for the best results
Frequently Asked Questions
How is grayscale different from desaturation?
Grayscale conversion uses perceptual luminance weights (approximately 0.299R + 0.587G + 0.114B) to match how the human eye perceives brightness. Simple desaturation averages the RGB channels equally, which can look flat.
Will grayscale images be smaller?
Yes. Grayscale images have 1 channel instead of 3 (RGB), so PNG files can be 60-70% smaller. JPEG compression is also more efficient with grayscale.
Can I convert back to color?
No. Color information is permanently removed during grayscale conversion. The original color data cannot be recovered.
Privacy & Security
This tool uses wasm-vips (libvips compiled to WebAssembly). The WASM binary (~5MB) is downloaded on first use and cached by your browser. All image processing happens locally on your device - your images are never uploaded to any server. This makes it safe for sensitive, private, or confidential images.