How to convert an image to grayscale or black-and-white
- Add your image — drag and drop it onto the box, click to browse, or paste from your clipboard. PNG, JPG, WebP, GIF and BMP all work.
- Pick a mode — choose Grayscale for a natural black-and-white photo look, or Black & white (threshold) for a hard two-tone result.
- Fine-tune it — in threshold mode, drag the slider to decide how much of the image turns white versus black. You can also tick Invert for a negative effect. The preview updates instantly.
- Download — click Download PNG to save the result. The file is built on your device and saved straight to your computer.
Grayscale vs. black-and-white: which should I use?
People often say "black-and-white" when they really mean grayscale — an image with no colour but a full spectrum of grey tones, from deep shadows to bright highlights. That is what most classic monochrome photographs are, and it is the mode you want for portraits, landscapes and any picture where you care about detail and depth.
True black-and-white uses only two colours: pure black and pure white, with nothing in between. This tool creates it by measuring each pixel's brightness (its luminance) and comparing it to a threshold you control. Raise the threshold and more of the image falls to black; lower it and more turns white. It is perfect for converting sketches, logos, signatures and scanned documents into clean line art, or for bold graphic and stencil-style effects.
Under the hood, brightness is calculated with the standard Rec. 601 luma formula (0.299·R + 0.587·G + 0.114·B), which weights green most heavily because the human eye is most sensitive to it. That gives a far more natural result than a flat average of the colour channels.
Is it private?
Yes. Your image is decoded with createImageBitmap and processed pixel-by-pixel on an HTML<canvas> — all inside your own browser tab. Nothing is uploaded to a server, nothing is stored, and nothing is logged. That makes it safe for private photos, confidential scans, ID documents and internal artwork. Because the work happens locally, it also keeps working offline once the page has loaded.
Frequently asked questions
Does this upload my image anywhere?
No — your image is processed locally in your browser and never leaves your device.
Will transparency be kept?
Yes. Transparent areas in a PNG stay transparent, because only the colour channels are changed and the alpha channel is preserved.
What does the Invert option do?
It flips light and dark, producing a photo-negative. In threshold mode that swaps which areas are black and which are white.
Can I convert many images at once?
This tool handles one image at a time so you can fine-tune the threshold for each. For batch format changes, try the image converter or compressor.
What file do I get back?
A lossless PNG. If you need a smaller JPG, run the PNG through our image converter afterwards.