What is Pixel?
A pixel is the smallest unit of a digital image - millions of pixels make up every photo and video
Last updated:
Pixel: Simple Definition
A pixel (picture element) is the smallest individual point in a digital image. Every digital photo, video frame, and screen display is made up of millions of tiny colored pixels arranged in a grid.
Each pixel stores color information as RGB values - red, green, and blue values from 0-255 that combine to create any color in the spectrum. Your smartphone screen has millions of pixels packed so tightly together they appear as one smooth image.
Color Depth
How many colors a pixel can express depends on its bit depth. The common 24-bit color allocates 8 bits each to red, green and blue, giving 256 levels per channel and about 16.7 million possible colors.[2] Many formats add a fourth alpha channel to record transparency, so each pixel may store four values rather than three.[1]
Device Pixels versus CSS Pixels
On the web a "pixel" is not always a physical dot. A CSS pixel is an abstract unit, and on high-density displays several physical device pixels render a single CSS pixel; the devicePixelRatio property reports this multiplier.[1] This distinction lets layouts stay a consistent visual size across screens of widely different sharpness.[1]
Subpixels and Rendering
Each on-screen pixel is physically built from smaller red, green and blue subpixels, and their arrangement varies between display technologies.[2] Some text-rendering techniques exploit these subpixels to sharpen edges, treating a single pixel as three independently addressable color stripes.[2]
How Pixels Work
When you take a 12-megapixel photo, your camera captures 12 million individual pixels. Each pixel records the exact color and brightness at that point in the scene. Zoom in far enough on any photo and you will see the individual colored squares.
The concept of pixels is important for image editing because it determines image quality limits. You cannot add detail by enlarging a low-resolution image - you just make the existing pixels bigger, creating a blurry, “pixelated” result.
Examples of Pixel
Smartphone photos
A 48-megapixel phone camera captures 48 million pixels. This allows heavy cropping while maintaining quality.
1080p video
Each frame of 1080p video contains 2,073,600 pixels (1920 x 1080). At 30fps, 62 million pixels are displayed per second.
Retina displays
Apple Retina displays pack 220-500+ pixels per inch, making individual pixels invisible to the naked eye at normal viewing distance.
Monitor resolution
A 4K monitor has 3840x2160 = 8,294,400 pixels. A 1080p monitor has 2,073,600 pixels.
Work With Your Files
Now that you understand the concept, use our free tools to convert, compress, and optimize your files.
Try Image Converter FreeFrequently Asked Questions
What is a megapixel?
One megapixel equals one million pixels. A 12MP camera captures 12 million individual pixels per photo.
What does “pixelated” mean?
A pixelated image has been enlarged beyond its resolution so individual pixels become visible as blocky colored squares.
Can I add pixels to make an image larger?
AI upscaling tools can intelligently add pixels, but traditional enlargement just stretches existing pixels resulting in blurriness.
How many pixels do I need for printing?
For print quality, you need 300 DPI (dots per inch). An 8x10 inch print needs 2400x3000 pixels minimum.
What is pixel density?
Pixel density (PPI - pixels per inch) measures how tightly pixels are packed on a screen. Higher PPI means sharper images.