In this post I’m going to talk about the relationship between pixels and inches for your computer monitor.
Your computer monitor is rated by pixels such as 1280 x 1024, which are width and length respectively. And if you have an image that is 300 x 200 pixels, you may ask how big will that be on my screen.
I will go through an exercise for a 21″ wide screen monitor rated for 1920 by 1080 pixels. The 21″ is measured diagonally from the lower left hand corner to the upper right hand corner. The screen ratio of width to height is 16:9, the newer wide screen models. The physical dimensions for this screen are 18.3 inches wide by 10.3 inches high.
So, it’s a very easy calculation, simply divide the pixels by the physical dimensions to get the pixels per inch for the screen. Do this for both sides. The results for the 21″ screen are, rounded off, 105 pixels per inch horizontally and 105 pixel per inch vertically.
So, the 300 x 200 pixel picture will be 2.86 inches by 1.9 inches on the screen.
For your screen you can get the physical dimensions from your manufacturer or simply take a ruler and measure it. Then you can run the calculations as above to get your specific pixels per inch for your monitor.
Interesting enough the older version 4:3 ratio screens have more total surface area than the newer 16.9 wide screens. The 4:3 ratio has 212 sq. inches whereas the 16:9 ratio has only 188 sq inches for a 21″ screen. The dimensions for the 4:3 ratio screen are 16.8″ wide by 12.6″ high.
What people are saying