What is my screen size?
Your browser reports your screen size in pixels, not inches. Here are the numbers it gives us, and a quick bank-card calibration that turns them into an estimated diagonal.
Your screen right now
Reading your screen…
Estimate the diagonal
Browsers cannot read the physical size of a screen, so we estimate it. Match the on-screen card to a real bank card and save: from that we work out how big a pixel is, and so how big your screen is.
Hold a bank card flat against your screen and keep your browser zoom at 100%.
Move the slider to match your card, then save.
What these numbers mean
- Screen size. Your screen's width and height in CSS pixels, the unit web pages are laid out in. On a scaled display it is smaller than the number of physical pixels.
- Pixel ratio. How many physical pixels make up one CSS pixel. A ratio of 2 or more means a high-density display.
- Physical pixels. The screen size times the pixel ratio. It is an estimate: your system may draw at a different resolution from the panel's native one.
- Diagonal. Matching the on-screen card to a bank card tells us how many CSS pixels fit in a millimetre, and that gives the size of the screen. Calibrate again if you change your browser zoom.
Questions
No. Browsers only report pixels, so no website can read the physical size of a screen. We estimate it instead: you match the card on the screen to a real bank card, which is 85.6 mm wide, and that tells us how big a pixel is.
Typically within a few percent, if you match the card carefully and keep your browser zoom at 100%. It is still an estimate. For the exact figure, check your device's specifications.
No. The numbers are read in your browser and shown only to you. Your calibration is saved in your browser's local storage, for this browser and display only, and it never leaves your device. Calibrate again if you change your browser zoom or use another screen. Like every page here, we count anonymous visits with a coarse device class (mobile, tablet or desktop), but never your exact screen size or calibration.