# How do I know the dpi of my laptop screen

My laptop is HP 250 G2 with 15.6” diagonal LED-backlit HD2 anti-glare (1366 x 768). Please How do I know the dpi value?

• For you It would be 100 ppi/dpi. Calculated using this website. – TheKB Jun 15 '16 at 18:41

1366 x 768 pixels is 1567 pixels diagonally (Pythagorean theorem, √(13662+7682)=1567; and you thought you would never use that).

If the screen measures 15.6" diagonally, 1567 pixels / 15.6" is approximately 100 pixels per inch.

You won't get an exact PPI number unless the manufacturer publishes it or you measure the screen. The advertised diagonal measurement is often a nominal number and may include a little of the display panel behind the bezel.

• Never thought pythagorean theorem has something to do with displays! – Mohammed Shareef C Jun 13 '17 at 6:58
• Pythagorean theorem has everything to do with Euclidean spaces, such as monitor surface – amuliar Dec 29 '17 at 17:32

Assuming you are using Windows 7:

• Go to `Control Panel` > `Appearance and Personalization` > `Display`
• In the left(blue) column, click `Set custom text size(DPI)`

A window titled `Custom DPI Scaling` will pop up. It will show what percent of the "normal size"(default monitor DPI) it is scaled to and will allow you to adjust it.

You should see a ruler in the middle. Below that it will say 9 point Segoe UI at X pixels per inch.

The X is your current DPI.

• Which version of windows? Mine says "9 point Segoe UI" rather than at X pixels per inch. – Journeyman Geek Jun 5 '16 at 23:31
• Windows 7. The exact message it says on my computer is "9 point Segoe UI at 144 pixels per inch" – Anonymous Jun 8 '16 at 23:09
• Might be worth mentioning the version then. Its not there in windows 10. – Journeyman Geek Jun 8 '16 at 23:20
• OK. Updated my answer. – Anonymous Jun 9 '16 at 0:59

as of DPI Calculator

• Display size: 13.6" × 7.65" = 103.96in² (34.54cm × 19.42cm = 670.72cm²)
• DPI = PPI = 100.45
• 0.2529mm dot pitch, 10091 PPI²

Try yourself: DPI Calculator

Formula:

PPI = √(pixels_horizontal^2 + pixels_vertical^2) / inches_diagonal

PPI = √(13662 + 7682) / 15.6 = 100.45

Therefore, 100.45 dpi