Pixel peeping calculator

The problem:
With high-megapixel digital cameras it isn't clear how close up to view them to determine image problems like focus and sharpness. Pixel peeping at 100% is certainly not the answer, but neither is the massive shrinking that "fit to window" does. So what zoom should you use?

The solution: Three easy steps
This calculator will recommend some reasonable viewing sizes. It will recommend the zoom you should set your viewer to when evaluating the detail of your photos.

Step 1: Measure your screen
Get a ruler that measures in inches and measure the size of the picture on your screen. I am talking about the physical number of inches your monitor can light up when you make a window full screen. Just measure across the whole screen, left to right then top to bottom.
The picture is inches wide by inches tall.

Step 2: Screen resolution
This is the number of pixels your screen displays, in width and height. If known it has already been filled in here. Otherwise, you may need to look in your display settings to fill this in.
My monitor is set to a resolution of pixels wide by pixels tall.

Step 3: Image dimensions
This is the number of pixels in the images your camera produces. Most image viewers will tell you the number of pixels, or you may be able to look at Properties or "Get Info" on one of the images to find out.
My images are pixels wide by pixels tall.