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Image to Grayscale Converter

Image to Grayscale Converter is part of Toolspire and is ready as soon as this page loads. Turn photos into grayscale or crisp black and white in one click — choose how colours become greys, fine-tune brightness and contrast, add a sepia tone, and convert as many images as you like.

Runs in this tabFreeNo account

On this page

What you can do here

Natural-looking greys

The default method keeps the brightness you see, so reds and blues don’t turn muddy or washed out.

Crisp black and white

Perfect for scans, signatures and line art — or dither photos for a newspaper-print look.

Batch conversion

Drop a whole folder of photos; every image uses the same settings and downloads together as a ZIP.

Before and after

Drag the slider over the preview to compare the original with the converted image.

Small files

True greyscale PNGs store one value per pixel instead of three, typically far smaller than colour PNGs.

Private

No uploads: conversion happens on your own device, even for large photos.

The sequence

How to convert an image to grayscale

  1. 1

    Add your images

    Drop one or more photos on the page, browse for them, or paste with Ctrl+V.

  2. 2

    Choose grey or black & white

    Pick Shades of grey or Black & white, and a method if you want a different look.

  3. 3

    Fine-tune

    Adjust brightness, contrast and intensity, or add a sepia tone. Drag the slider on the preview to compare.

  4. 4

    Download

    Download each image, or Download all (ZIP) — as JPG, PNG or WebP.

Worth knowing

  • Image to Grayscale Converter on Toolspire: converts to shades of grey or pure black and white, with a before-and-after slider to compare.
  • Seven ways to turn colour into grey: Luminance (Rec. 709 in linear light, the default), Rec. 601, average, lightness, or a single red, green or blue channel.
  • Black and white uses an automatic threshold (Otsu’s method) or your own, with optional Floyd–Steinberg dithering to keep shading in photos.
  • Adjust intensity (partly desaturated looks), brightness and contrast, and add a sepia tone.
  • Converts many images at once and downloads them as a ZIP — as JPG, PNG or WebP. Neutral grey PNGs are saved as true 8-bit greyscale (1-bit for black and white), so files are much smaller.
  • Works with JPG, PNG, WebP and HEIC. Images are processed in this tab and location data is removed.

Which grayscale method should I use?

MethodFormulaBest for
Luminance0.2126 R + 0.7152 G + 0.0722 B, in linear lightPhotos — keeps the brightness people see
Rec. 6010.299 R + 0.587 G + 0.114 BMatching most other apps and older software
Average(R + G + B) ÷ 3Quick, simple results
Lightness(max + min) ÷ 2A soft, low-contrast look
Red channelRDramatic skies and smooth skin, like a red filter on film
Green / blue channelG or BFoliage detail (green) or a moody, grainy look (blue)

Grayscale or black and white?

Grayscale keeps up to 256 shades of grey, so a photo still shows every tone — this is what most people mean by a black-and-white photo.

Black and white (1-bit) uses only pure black and pure white. It suits scanned documents, signatures, stamps, logos and line drawings, and makes the smallest files. Turn on dithering to fake grey tones with dots when converting photos.

FAQ

Questions about Image to Grayscale Converter

Where does Image to Grayscale Converter run?

Image to Grayscale Converter runs in this tab on Toolspire. What you type or drop in is not sent to us and is not stored on a server.

How do I convert a photo to black and white?

Drop the photo here: it is converted to grayscale straight away. Drag the slider to compare, adjust contrast if you like, then press the download button.

Is grayscale the same as black and white?

In everyday language, yes — a "black and white photo" is grayscale, with many shades of grey. Choose Black & white here for pure black and white only, for example for scanned documents.

Are my photos uploaded?

No. Everything happens in this tab, so your photos stay on this device.

Can I convert several images at once?

Yes. Add as many images as you want; they all use the same settings, and Download all (ZIP) saves them in one file.

Why is the grayscale PNG smaller than the original?

A colour PNG stores red, green and blue for every pixel. A greyscale PNG stores just one grey value (or a single bit for black and white), so the same picture takes far less space — with no loss of quality.

Can I make a sepia photo?

Yes. Choose Sepia under Tone for the warm brown look of old photographs; it works in both grey and black-and-white modes.

Keep going

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