Image / Inspect
Image Histogram
See an image's brightness and red, green, and blue histograms, with the share of clipped highlights and shadows, for checking exposure.
Image Histogram: Every pixel is counted by its value from 0 to 255 in each colour channel, and by its brightness using the ITU-R BT.601 weights (0.299 red, 0.587 green, 0.114 blue). The counts matched Pillow's histogram exactly on test images. Clipped pixels are those with a channel at 0 or 255, where detail is lost. Runs 100% locally in your browser with zero server file uploads.
- Category
- Image tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Click, drag and drop, or paste · stays on this device
Each chart counts how many pixels have each value from 0 (left) to 255 (right). A peak pressed against the right edge means blown highlights; against the left, crushed shadows. Brightness uses the ITU-R BT.601 weights. Fully transparent pixels are left out, and nothing is uploaded.
Reading the chart
The left edge is pure black (0) and the right edge pure white (255). A histogram bunched to the left is a dark, perhaps underexposed image; bunched to the right, a bright one. A gap at either end means the image never reaches full black or white, which often looks flat.
To read the exact colour of one pixel, use the image color picker; to see the camera's settings, the EXIF viewer.
Brightness weights
Brightness counts green most and blue least, because the eye is most sensitive to green: 0.299 × red + 0.587 × green + 0.114 × blue, the BT.601 weights used for standard-definition video and by most image editors' greyscale conversion.
How to use it
- Choose a photo or image.
- Read the brightness and colour histograms.
- Check the clipped highlights and shadows.
Privacy & limitations
The image is read in your browser and never uploaded.
Related tools
Frequently asked questions
What does a good histogram look like?
There is no single right shape: a snow scene sits to the right and a night scene to the left. What to watch for is a tall spike against either edge, which means detail lost to pure white or black.
Why read the colour channels separately?
One channel can clip while brightness looks fine, such as a red flower with its red channel at 255 and no texture left; the RGB charts show that.
Does it read the camera's raw data?
No: it reads the image as saved, after the camera or editor processed it, which is what viewers see.
Free tool · runs in your browser · no account required