Grayscale Image Converter
Convert any image to black and white with a choice of four conversion methods — Rec. 709 luminosity, the older Rec. 601 luma weighting, a plain average of the three channels, or HSL lightness — and a strength slider for a partly desaturated look. Each method weights red, green and blue differently, so the same photo can come out noticeably lighter or darker depending on which you pick. The conversion runs on your device using the canvas API; the picture is never uploaded.
Weights green highest because the eye is most sensitive to it. The default in most photo editors.
Below 100% the original colour shows through, giving a faded rather than fully grey result.
Frequently asked questions
Why do the different grayscale methods give different results?
Each method weights the red, green and blue channels differently: Rec. 709 gives green the most weight because the eye is most sensitive to it, Rec. 601 leans more on red, a plain average treats all three equally, and HSL lightness uses only the brightest and darkest channel. A saturated red comes out at grey level 54 under Rec. 709 but 76 under Rec. 601.
Which grayscale method should I use?
Rec. 709 luminosity is the default in most photo editors and usually looks the most natural, so it is the right starting point unless you are matching output from an older system, in which case Rec. 601 is the closer match.
Can I make an image only partly grayscale?
The strength slider blends between the original and the fully grey version, so a value like 60% keeps a muted trace of the original colour rather than removing it entirely.
Does converting to grayscale make the file smaller?
Usually yes for JPEG and WebP, because the chroma channels carry almost no information after conversion, but the saving depends on the image and the quality setting rather than being guaranteed.
Is my photo uploaded when I convert it to grayscale?
No photo is uploaded — the file is decoded and converted by your own browser through the canvas API, so it never leaves your device.
Related tools
Invert Image Colors
Create a photo negative in your browser, with per-channel control and an adjustable blend toward the negative.
Color Desaturation Tool
Fade a colour toward grey in even steps, and see how zero saturation differs from a true greyscale conversion.
Image Editor
Resize, crop, rotate, flip and compress images online, one at a time or in batch, all inside your browser.