What Does Megapixel Mean?

By Joe Fletcher

One of the most prominent features of digital cameras is the number of megapixels the camera has. While most people know that more is usually better, understanding the role between megapixels, or MPs, and the resolution of the photos that a camera will take is vital if you want to get quality photos.

Pixels and Megapixels

Simply put, a pixel is the smallest component of a digital image: a tiny square dot. If you look at a computer or television screen very closely or with the help of a magnifying glass, you can see the pixels. A megapixel is one million pixels.

Megapixels and Resolution

The resolution of a digital camera is defined by the number of pixels it uses. Resolution is viewed as a formula such as 4200 pixels by 2800 pixels, or simply 4200 x 2800. This equation relates to the number of pixels on the horizontal axis and vertical axis. When the numbers are multiplied and divided by one million, you get the megapixels for that camera. For example, 4200 x 2800 equals 11,760,000 pixels, which is rounded up as 12 megapixels. Printed at 300 dots per inch, a photo taken with a 12 megapixel camera would be a 16-by-24 inch print.


Megapixels are considered an important measurement of a digital camera's quality. More megapixels means higher resolution, larger prints and greater detail than fewer megapixels. For example, compared to a 12 megapixel camera, an older camera with only 3 megapixels has a resolution of only 2048 by 1536 pixels. Printed out, this would be just a 5-by-7 inch photo. Of course, the number of megapixels should only be one consideration when buying a camera, but it's a good one to start with.


Before paying more than you budgeted for because of a camera's megapixel count, it's a good idea to consider what you will be using the camera for. If you plan to print posters or large prints, the investment may be worth it. However, higher resolution photos require more space for storage than smaller photos.

Pixels and Sensor Size

Not all pixels are created equal. Just as important as the number of megapixels in higher-end cameras like DSLRs, are the size of the pixels. Pixel size is determined by a digital camera's light sensor. A sensitive sensor has smaller pixels, but it might not have as many pixels. For example, an inexpensive point-and-shoot camera may have the same number of megapixels as a DSLR camera. However, if you read the specs on each camera you will often find that the DSLR has much smaller pixels, meaning the images are sharper and with a better overall resolution.