Image to Grayscale — Free Online Tool
Convert any image to grayscale using the ITU-R BT.601 luminance formula (Y = 0.299R + 0.587G + 0.114B), which matches human perception of color brightness. A side-by-side preview shows the original and grayscale versions before you download.
100% client-side. No uploads. Your data never leaves your browser.
How to use Image to Grayscale
- Upload an image.
- The grayscale version appears in a side-by-side preview.
- Verify the result looks correct.
- Click 'Download' to save the grayscale image as PNG.
Frequently Asked Questions
Why use the ITU-R formula instead of averaging RGB values?
Human eyes are more sensitive to green than red and least sensitive to blue. The ITU-R formula weights channels accordingly, producing perceptually accurate luminance.
Does this affect the alpha channel?
No. Transparency is preserved in PNG output. The grayscale conversion only affects the RGB channels.
Can I download in color formats other than PNG?
Currently the output is PNG. Convert the grayscale PNG to JPEG/WebP using the Image Converter if needed.
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