You just shot a video on your phone and the editing app asks for the aspect ratio, or you are comparing two monitors — one is 1920×1080 and the other is 2560×1440 — and you want to know which is genuinely sharper. Enter the width and height in pixels and this calculator returns the aspect ratio as a decimal (1.78 for classic 16:9), the total pixel count, the megapixel figure, and the screen diagonal in the same units using the Pythagorean theorem. For example, 1920×1080 gives a ratio of about 1.78 — that is 16:9, the widescreen standard — a diagonal of roughly 2,203 pixels, and 2.07 megapixels, which explains why a 1080p screenshot looks soft when printed large. Photographers use the megapixel readout to check whether a crop still holds enough detail, streamers use the ratio to match canvas sizes without black bars, and shoppers use the total pixels to compare a 4K TV (3840×2160, about 8.29 MP) against a 1440p monitor. The formulas are simple division and multiplication, but getting all four answers from one pair of numbers saves a spreadsheet.

With the pre-filled defaults — Width (pixels) 1,920, Height (pixels) 1,080 — the Aspect Ratio Calculator returns Aspect Ratio (decimal) 1.7778, Diagonal (same unit) 2,203, Total Pixels 2,073,600, Megapixels 2.07. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.